Provide default credentials for srvrco (temporary)

Use hard-coded default credentials for srvrco when GitHub secrets are
not installed.

This is a security issue for srvrco, but a fix seems to be difficult.

Author: tlhackque

.github/workflows/run-tests-staging-duckdns.yml

@@ -12,7 +12,7 @@ on:
     branches:
       - master
 env:
-  DUCKDNS_TOKEN: ${{ secrets.DUCKDNS_TOKEN }}
+  DUCKDNS_TOKEN: ${{ secrets.DUCKDNS_TOKEN == '' && '1d616aa9-b8e4-4bb4-b312-3289de82badb' || secrets.DUCKDNS_TOKEN }}
 jobs:
   test-centos7-duckdns:
     runs-on: ubuntu-latest

.github/workflows/run-tests-staging-dynu.yml

@@ -12,7 +12,7 @@ on:
     branches:
       - master
 env:
-  DYNU_API_KEY: ${{ secrets.DYNU_API_KEY }}
+  DYNU_API_KEY: ${{ secrets.DYNU_API_KEY == '' && '65cXefd35XbYf36546eg5dYcZT6X52Y2' || secrets.DYNU_API_KEY }}
 jobs:
   test-centos7-dynu:
     runs-on: ubuntu-latest