Fix webhook secret file names (#3201)

Here's what happened:
 - I submitted PR #3177
 - Ria submitted feedback inline, I accepted it. The suggestions were
   merged into the remote branch.
 - the patch had conflicts with main
 - I resolved the conflicts locally and force-pushed to the remote branch. My
   local branch didn't have Ria's suggestions and the force-push removed
   them

This patch brings back Ria's suggestions so I included her as a
co-author.

Sorry!

Co-authored-by: Eleftheria Stein-Kousathana <eleftheria@stacklok.com>

deployment/helm/templates/deployment.yaml

@@ -84,9 +84,9 @@ spec:
           - name: "MINDER_FLAGS_GO_FEATURE_FILE_PATH"
             value: "/flags/flags-config.yaml"
           - name: "MINDER_WEBHOOK_CONFIG_WEBHOOK_SECRET_FILE"
-            value: "/secrets/app/repo_webhook_secret"
+            value: "/secrets/app/github_repo_webhook_secret"
           - name: "MINDER_WEBHOOK_CONFIG_PREVIOUS_WEBHOOK_SECRET_FILE"
-            value: "/secrets/app/repo_fallback_webhook_secret"
+            value: "/secrets/app/github_repo_fallback_webhook_secret"
           {{- if .Values.deploymentSettings.extraEnv }}
           {{- toYaml .Values.deploymentSettings.extraEnv | nindent 10 }}
           {{- end }}