Update workflow trigger to make sure Docker image build is also triggered on push to a tag (#1147)

* Update workflow trigger to make sure Docke image build is also triggered
on push to a branch.

* Add workflow_dispatch trigger so workflow can also be triggered
manually.

Author: tomaz-s1

.github/workflows/agent-build.yml

@@ -5,9 +5,12 @@ on:
   push:
     branches:
       - master
+    tags:
+      - v*.*.*
   pull_request:
     branches:
       - master
+  workflow_dispatch:
 
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