action.yml: update gitops pusher to get precedence fix

Update gitops pusher dependency to get a fix for credential precedence.
Previously users attempting to authenticate with an API and the latest
version of the action would hit an error due to the gitops pusher
incorrectly trying to do a token exchange operation.

Updates #71

Signed-off-by: Mario Minardi <mario@tailscale.com>

Author: mpminardi

action.yml

@@ -40,7 +40,7 @@ runs:
         exit 1
     - uses: actions/setup-go@4dc6199c7b1a012772edbd06daecab0f50c9053c # v6.1.0
       with:
-        go-version: 1.25.5
+        go-version: 1.25.6
         cache: false
     - name: Fetch ID token
       if: ${{ inputs['oauth-client-id'] != '' && inputs['audience'] != '' }}
@@ -61,5 +61,5 @@ runs:
         TS_ID_TOKEN: "${{ steps.fetch-id-token.outputs.id_token }}"
         TS_API_KEY: "${{ inputs.api-key }}"
         TS_TAILNET: "${{ inputs.tailnet }}"
-      run: go run tailscale.com/cmd/gitops-pusher@4c37141ab780dbf6c037bd64fe48ab330441ad06 "--policy-file=${{ inputs.policy-file }}" "${{ inputs.action }}"
+      run: go run tailscale.com/cmd/gitops-pusher@b4d39e2fd92538384aa7388fdbeda0ec51973bfc "--policy-file=${{ inputs.policy-file }}" "${{ inputs.action }}"