Error on invocation: "No module named mssqlcli"

Hello, I am on macOS Catalina 10.15.7, trying to use mssql-cli to query a SQL Server DB, I installed using `pip3 install mssql-cli`, but for some reason the CLI thinks it should be pointed at Python 2.7:

```sh
❯ pip3 install mssql-cli
< ... >
❯ mssql-cli
/System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python: No module named mssqlcli
```

for reference here is the version info of my various relevant commands:

```sh
❯ which pip3
/Library/Frameworks/Python.framework/Versions/3.8/bin/pip3
❯ pip3 --version
pip 21.1.3 from /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pip (python 3.8)
❯ which python3
/Library/Frameworks/Python.framework/Versions/3.8/bin/python3
❯ python3 --version
Python 3.8.2
❯ which pip
/Library/Frameworks/Python.framework/Versions/3.8/bin/pip
❯ pip --version
pip 21.1.3 from /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pip (python 3.8)
❯ which python
/usr/bin/python
❯ python --version
Python 2.7.16
```

Any pointers for un-crossing the wires to point at the correct directory on cli startup would be appreciated.

Reproduce the failure using the shown Python 3.8 and Python 2.7 paths, starting at the installed mssql-cli command entry point. Compare how the command resolves mssqlcli with the interpreter used by pip3, then verify that mssql-cli uses the installed Python 3 package and no longer raises the module error.

Scritto dal modello di indicizzazione a partire dal testo della issue.