feat: swap to stepsecurity action for GPG (#16)

Author: AfterHistory

.github/workflows/upstream-sync.yml

@@ -34,7 +34,7 @@ jobs:
           fetch-depth: 0
 
       - name: Import GPG key
-        uses: crazy-max/ghaction-import-gpg@e89d40939c28e39f97cf32126055eeae86ba74ec # v6.3.0
+        uses: step-security/ghaction-import-gpg@69c854a83c7f79463f8bdf46772ab09826c560cd # v6.3.1
         with:
           gpg_private_key: ${{ secrets.GPG_PRIVATE_KEY }}
           passphrase: ${{ secrets.PASSPHRASE }}