`gcp_compute_route` fails every time for more than a year

##### SUMMARY

`gcp_compute_route` fails with a TypeError.

This is a transfer of https://github.com/ansible/ansible/issues/55153.

It is more than a year that you are offering a module that breaks your users' apps. Your modules [deprecated community ones](https://github.com/ansible/ansible/pull/27252) that could at least perform what they claimed they do. Could there at least be some professionalism and some community feedback here?

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME

`gcp_compute_route`

##### ANSIBLE VERSION

```paste below
ansible 2.10.0.dev0
config file = None
configured module search path = ['/home/nikos/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python3.8/site-packages/ansible
executable location = /usr/bin/ansible
python version = 3.8.1 (default, Jan 22 2020, 06:38:00) [GCC 9.2.0]
```

##### CONFIGURATION

```paste below
None
```

##### OS / ENVIRONMENT

irrelevant

##### STEPS TO REPRODUCE

```yaml
gcp_compute_route:
name: name-here
dest_range: 192.168.0.0/24
next_hop_instance:
selfLink: zones/europe-west1-b/instances/vpn
priority: 100
```

##### EXPECTED RESULTS

No errors.

##### ACTUAL RESULTS

```paste below
The full traceback is:
Traceback (most recent call last):
File "", line 102, in
File "", line 94, in _ansiballz_main
File "", line 40, in invoke_module
File "/usr/lib/python3.8/runpy.py", line 206, in run_module
return _run_module_code(code, init_globals, run_name, mod_spec)
File "/usr/lib/python3.8/runpy.py", line 96, in _run_module_code
_run_code(code, mod_globals, init_globals,
File "/usr/lib/python3.8/runpy.py", line 86, in _run_code
exec(code, run_globals)
File "/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible_collections/google/cloud/plugins/modules/gcp_compute_route.py", line 539, in
File "/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible_collections/google/cloud/plugins/modules/gcp_compute_route.py", line 391, in main
File "/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/basic.py", line 2043, in exit_json
File "/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/basic.py", line 2012, in _return_formatted
File "/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/basic.py", line 722, in warn
File "/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/common/warnings.py", line 18, in warn
return _formatwarnmsg_impl(msg)
TypeError: warn requires a string not a
fatal: [slagfalt-vpn -> localhost]: FAILED! => {
"changed": false,
"module_stderr": "Traceback (most recent call last):\n File \"\", line 102, in \n File \"\", line 94, in _ansiballz_main\n File \"\", line 40, in invoke_module\n File \"/usr/lib/python3.8/runpy.py\", line 206, in run_module\n return _run_module_code(code, init_globals, run_name, mod_spec)\n File \"/usr/lib/python3.8/runpy.py\", line 96, in _run_module_code\n _run_code(code, mod_globals, init_globals,\n File \"/usr/lib/python3.8/runpy.py\", line 86, in _run_code\n exec(code, run_globals)\n File \"/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible_collections/google/cloud/plugins/modules/gcp_compute_route.py\", line 539, in \n File \"/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible_collections/google/cloud/plugins/modules/gcp_compute_route.py\", line 391, in main\n File \"/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/basic.py\", line 2043, in exit_json\n File \"/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/basic.py\", line 2012, in _return_formatted\n File \"/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/basic.py\", line 722, in warn\n File \"/tmp/ansible_gcp_compute_route_payload_yo8rsw04/ansible_gcp_compute_route_payload.zip/ansible/module_utils/common/warnings.py\", line 18, in warn\n return _formatwarnmsg_impl(msg)\nTypeError: warn requires a string not a \n",
"module_stdout": "",
"msg": "MODULE FAILURE\nSee stdout/stderr for the exact error",
"rc": 1
}
```

Start in ansible_collections/google/cloud/plugins/modules/gcp_compute_route.py, especially main at the traceback's reported line, and follow the exit path into ansible/module_utils/common/warnings.py. Reproduce the supplied route configuration and verify that the module completes without the TypeError and reports the expected successful result.

Written by the indexing model from the issue text.