fix: Correct regex character class in tag validation

The regex was using \-\. which creates an invalid character range in bash.
Changed to .- (without escaping) which works correctly for matching
hyphens and dots in prerelease tags.

Fixes Docker build workflow failure during tag validation.

Author: jamesbrink

.github/workflows/publish.yml

@@ -97,7 +97,7 @@ jobs:
     - name: Validate tag format
       if: github.event_name == 'workflow_dispatch'
       run: |
-        if [[ ! "${{ inputs.tag }}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(-[a-zA-Z0-9\-\.]+)?$ ]]; then
+        if [[ ! "${{ inputs.tag }}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(-[a-zA-Z0-9.-]+)?$ ]]; then
           echo "❌ Invalid tag format. Expected: v1.2.3 or v1.2.3-alpha"
           exit 1
         fi