github-ci: pin actions/upload-artifact to newer version

Required for the newer version of download-artifact in use due to sync
with master.

.github/workflows/builds.yml

@@ -142,7 +142,7 @@ jobs:
           cd ..
           tar zcf suricata-verify.tar.gz suricata-verify
       - name: Uploading prep archive
-        uses: actions/upload-artifact@0b7f8abb1508181956e8e162db84b466c27e18ce
+        uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882
         with:
           name: prep
           path: |