[skip ci] Fix update image tag bug (#6481)

Signed-off-by: Nquicksilver <zhifeng.zhang@zilliz.com>

.github/workflows/publish-builder.yaml

@@ -56,11 +56,11 @@ jobs:
         continue-on-error: true
         shell: bash
         run: |
-          sed -i "s#$DATE_VERSION=.*#DATE_VERSION=${{ steps.extracter.outputs.version }}#g" .env
+          sed -i "s#^DATE_VERSION=.*#DATE_VERSION=${{ steps.extracter.outputs.version }}#g" .env
           git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git config --local user.name "github-actions[bot]"
           git add .env
-          git commit -m "Update Builder Image Changes"
+          git commit -m "Update Builder image changes"
       - name: Create Pull Request
         id: cpr
         if: success() && github.event_name == 'push' && github.repository == 'milvus-io/milvus' && matrix.os == 'ubuntu18.04'
@@ -72,9 +72,9 @@ jobs:
           signoff: false
           branch: update_builder_${{ github.sha }}
           delete-branch: true
-          title: '[automated] Update Builder Image Changes'
+          title: '[automated] Update Builder image changes'
           body: |
-            Update Builder Image Changes
+            Update Builder image changes
 
             Signed-off-by: ${{ github.actor }} ${{ github.actor }}@users.noreply.github.com
       - name: Check outputs

.github/workflows/publish-test-images.yaml

@@ -60,11 +60,11 @@ jobs:
         shell: bash
         working-directory: tests/docker
         run: |
-          sed -i "s#$IMAGE_TAG=.*#IMAGE_TAG=${{ steps.extracter.outputs.version }}-${{ steps.extracter.outputs.sha_short }}#g" .env
+          sed -i "s#^IMAGE_TAG=.*#IMAGE_TAG=${{ steps.extracter.outputs.version }}-${{ steps.extracter.outputs.sha_short }}#g" .env
           git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git config --local user.name "github-actions[bot]"
           git add .env
-          git commit -m "Update Pytest Image Changes"
+          git commit -m "Update Pytest image changes"
       - name: Create Pull Request
         id: cpr
         if: success() && github.event_name == 'push' && github.repository == 'milvus-io/milvus'
@@ -76,9 +76,9 @@ jobs:
           signoff: false
           branch: update_pytest_${{ github.sha }}
           delete-branch: true
-          title: '[automated] Update Pytest Image Changes'
+          title: '[automated] Update Pytest image changes'
           body: |
-            Update Pytest Image Changes
+            Update Pytest image changes
 
             Signed-off-by: ${{ github.actor }} ${{ github.actor }}@users.noreply.github.com
       - name: Check outputs