Mismatched version warning for identical versions (.patch vs .dev.patch)

After updating `patch-package` from version 6.1.2 to 6.2.0 in [my project](https://github.com/balena-io/balena-cli), running `npm install --production` resulted in the error:
```
Error: Patch file found for package qqjs which is not present at node_modules/qqjs
If this package is a dev dependency, rename the patch file to
qqjs+0.3.10.dev.patch
```

Where `qqjs` is indeed a **transitive** dev dependency. Renaming the patch file to `.dev.patch` avoided the error, but led to the following warning when running `npm install` **without** `--production`:

```
Warning: patch-package detected a patch file version mismatch
Don't worry! This is probably fine. The patch was still applied
successfully. Here's the deets:

Patch file created for
qqjs@0.3.10.dev
applied to
qqjs@0.3.10
At path
node_modules/qqjs

This warning is just to give you a heads-up. There is a small chance of
breakage even though the patch was applied successfully. Make sure the package
still behaves like you expect (you wrote tests, right?) and then run

patch-package qqjs

to update the version in the patch file name and make this warning go away.
```

Following the printed advice and running `patch-package qqjs` does not make any difference: the patch file is not modified, and the warning persists.

I gather / understand that the only "version mismatch" is the `.dev` at the end of the version number ("0.3.10" _vs._ "0.3.10.dev"). Could the warning be avoided in this case? End users may get alarmed at _"There is a small chance of breakage."

I have a very simple pull request that "fixes" (works around?) this issue, by ignoring `.dev` in the version comparison. Feel free to replace it with a more proper fix! Thank you.