make build docker image a triggable workflow

Author: eduardo-munoz-dremio

.github/workflows/docker.yaml

@@ -1,10 +1,13 @@
 name: Docker Image builder
 
 on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
+  workflow_dispatch:
+    inputs:
+      repository:
+        default: us-west1-docker.pkg.dev/dremio-1093/dremio
+        description: Repository to push the image to. Image name is fixed to 'dremio-mcp-server' and tag is calculated at runtime
+        required: true
+        type: string
 
 jobs:
   build:
@@ -65,7 +68,6 @@ jobs:
           head_sha=$(git rev-parse --short HEAD)
           timestamp=$(date -u +"%Y%m%d%H%M%S")
 
-          # This tag follows the same convention as https://github.com/dremio/opensearch-k8s-operator/blob/main/.github/workflows/publish.yaml#L17
           tag="${timestamp}-${head_sha}"
           
           echo "tag=$tag" | tee -a "$GITHUB_OUTPUT"
@@ -82,6 +84,6 @@ jobs:
           context: .
           push: true
           tags: |
-            us-west1-docker.pkg.dev/dremio-1093/dremio/dremio-mcp-server:${{ steps.tag.outputs.tag }}
+            ${{ inputs.repository }}/dremio-mcp-server:${{ steps.tag.outputs.tag }}