Document how to manually build the release archive (#2607)

I've added information on how to manually build the release archive
(`bazel build //distribution:release`). As I see this hasn't been
mentioned anywhere, so I think README.md is the right place.

Signed-off-by: Vadim Smal <[email protected]>
Co-authored-by: Vadim Smal <[email protected]>

Author: CognitiveDisson

README.md

@@ -100,6 +100,8 @@ ones we’ve officially tested with.
 From the
 [release you wish to use](https://github.com/MobileNativeFoundation/rules_xcodeproj/releases),
 copy the Bzlmod or WORKSPACE snippet into your repository.
+If you want to manually build a release archive, you can use this command:
+`bazel build //distribution:release`.
 
 ## Usage