Added ability to specify milestone for a version

CHANGELOG.rst

 v0.8.12
 =======
 
+:Milestone: Beta 3
+
 * When album cover art is not provided by the server, a default album art image
   is used (Contributed by @sentriz.)
 * **New Setting**: *Serve locally cached files over the LAN to Chromecast

cicd/publish-gitlab-release.sh

@@ -15,6 +15,10 @@ if [[ $(head -n 1 CHANGELOG.rst) == "${CI_COMMIT_TAG}" ]]; then
             fi
             first=0
         fi
+
+        if [[ "${l:0:11}" == ":Milestone:" ]]; then
+            milestone="$(echo $l | sed -n 's/:Milestone: \(.*\)/\1/p')"
+        fi
     done < CHANGELOG.rst
 
     # i is now the index of the line below the second header.
@@ -30,6 +34,11 @@ fi
 
 description=$(echo "$description" | rst2html5 --no-indent --template "{body}" | sed -e 's/\"/\\\"/g')
 
+milestones=""
+if [[ "${milestone}" != "" ]]; then
+    milestones=",\"milestones\":[\"${milestone}\"]"
+fi
+
 # Determine whether or not to include the Flatpak build.
 failed=$(curl \
     --header "PRIVATE-TOKEN: ${RELEASE_PUBLISH_TOKEN}" \
@@ -57,6 +66,7 @@ data="
     \"name\": \"${CI_COMMIT_TAG}\",
     \"tag_name\": \"${CI_COMMIT_TAG}\",
     \"description\": \"${description}\"
+    ${milestones}
     ${assets}
 }
 "