update GH action for attest-build-provenance

dependabot flagged this in #55. Pinning to `@v2` should let the minor and patch
version update automatically

Author: trey-stafford

.github/workflows/build-and-release.yml

@@ -46,7 +46,7 @@ jobs:
           path: dist
 
       - name: Generate artifact attestation for sdist and wheel
-        uses: actions/attest-build-provenance@v1.4.3
+        uses: actions/attest-build-provenance@v2
         with:
           subject-path: "dist/*"