Fix rate limits in CI (#436)

Still hitting BSR rate limits; add a token to the other steps that use
them.

Ref:
https://github.com/bufbuild/protovalidate-python/actions/runs/22731504577/job/65921498464

Author: stefanvanburen

.github/workflows/ci.yaml

@@ -41,4 +41,8 @@ jobs:
         env:
           BUF_TOKEN: ${{ secrets.BUF_TOKEN }}
       - run: make test
+        env:
+          BUF_TOKEN: ${{ secrets.BUF_TOKEN }}
       - run: make conformance
+        env:
+          BUF_TOKEN: ${{ secrets.BUF_TOKEN }}