gh-workflow: switch to wmime

Author: jengelh

.github/workflows/build.yml

@@ -25,7 +25,7 @@ jobs:
     - name: clone-vmime
       uses: actions/checkout@v3
       with:
-        repository: kisli/vmime
+        repository: grommunio/wmime
         path: vmime
     - name: clone-libHX
       uses: actions/checkout@v3