Merge bitcoin/bitcoin#26445: .python-version: bump patch version to 3.6.15

29fa38a .python-version: bump patch version to 3.6.15 (Sjors Provoost)

Pull request description:

  I'm unable to build Python 3.6.12 using PyEnv on macOS 13.0 as well as Ubuntu 22.10. Bumping the patch version fixes that issue on both systems.

  A workaround is to add `.python-version` to your local git excludes and then do `pyenv local 3.6.15`, but this won't persist when you switch branches. Another workaround is to disable `pyenv`, but then you're potentially not running the test suite against the oldest supported Python version.

ACKs for top commit:
  MarcoFalke:
    concept ACK 29fa38a

Tree-SHA512: 60ecf76c957456fe4ece9e92c30866b27aba32d5bdb1696495281c2f7ef7a1fc30226e8992d55bf6f45e430b7588e05fbe49de7138aefab5597dd52bd4f021c0

Author: MacroFake

.python-version

@@ -1 +1 @@
-3.6.12
+3.6.15