fix: [Make] Create windows binaries with .exe extension

[zalgonoise]

When fetching Venom binaries, I noticed that Windows releases didn't include an extension. For Windows, it means that the users will face the program-picker prompt due to a lack of extension, and would have to add it manually.

This PR changes the CROSS_COMPILED_BINARIES make target in .build/go.mk to check if the current target OS is windows, and if so, changing the filename to include the .exe extension.

I assume that the point of BINARIES is precisely this, but probably due to some lack of Make syntax knowledge, I couldn't figure out why IS_WINDOWS isn't being recognized :)

That being the case, I am opening a suggestion to leverage the GOOS env var taken from the get_os_from_binary_file call, and changing the filename if the OS is windows.

Any suggestions for changes are welcome, provided that we are able to distribute windows binaries with the proper extension :)

[zalgonoise]

Note: the force-push was to add the sign-off mark to the commit, in compliance with the DCO :)

[yesnault]

Thank you @zalgonoise

[ovh-cds]

CDS Report build-venom-a#190.0 ✘

• Build
  • Build ✔
  • Unit Tests ✔
• Tests
  • Acceptance Tests ✘