.github/workflows: update pypa/gh-action-pypi-publish

There is a security fix in 1.13.0 and dependabot insists.

Change-Id: I346de5711188a6c2b03d1416b7bda4d614976c9c
Reviewed-on: https://code-review.googlesource.com/c/re2/+/64050
Reviewed-by: Alan Donovan <adonovan@google.com>

.github/workflows/python.yml

diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index fbd1222..beec8ca 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -251,6 +251,6 @@
         shell: bash
         working-directory: python
       - if: inputs.build >= 1
-        uses: pypa/gh-action-pypi-publish@v1.12.4
+        uses: pypa/gh-action-pypi-publish@v1.13.0
         with:
           packages-dir: python/dist