gpgme: package python3 bindings as well - require python3 for build

[michael-paddle]

Currently gpgme doesn't package the python3 bindings, only the python2.7 ones. By adding a build dependency to python (== python 3) we ensure that the python3 bindings are also built and packaged.

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• [/] Have you checked that there aren't other open pull requests for the same formula update/change?
• [/] Have you built your formula locally with brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• [/] Does your build pass brew audit --strict <formula> (after doing brew install <formula>)?

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A note on this PR; during testing I discovered that if you have standard python.org python installed then it does't find the bindings. I wonder if there is anything that could be easily done to make homebrew bindings automatically visible to python.org python. The debian solution is to have a dist-packages directory which is supposed to be visible in all python versions but come after the site-packages allowing packages there to be used but overridden as needed.

[fxcoudert]

When building Python bindings, we usually make the python requirement for runtime too… after all, the bindings are otherwise useless.

[michael-paddle]

@fxcoudert ; I'd propose an exception in this case because the package is useful if you only want the C bindings but the other language bindings have already been included. If you want to use it with python then, obviously, you need to have python installed.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[michael-paddle]

@Stale bot please don't mark this issue as stale; It's waiting for @fxcoudert to have time to reply.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[fxcoudert]

Oops. Completely forgot about that one. I suppose it's okay-ish.

[fxcoudert]

@BrewTestBot test this please