Increment IJ plugin snapshot version (#5184)

Co-authored-by: github-actions <[email protected]>

Author: github-actions[bot]

intellij-plugin/gradle.properties

@@ -35,4 +35,4 @@ javaVersion=17
 kotlin.stdlib.default.dependency=false
 
 # Snapshot version, automatically incremented by the CI
-snapshotVersion=27
+snapshotVersion=28

intellij-plugin/snapshots/plugins.xml

@@ -1,9 +1,9 @@
 <plugins>
   <plugin
       id="com.apollographql.ijplugin"
-      url="https://repsy.io/mvn/bod/apollo-intellij-plugin/com/apollographql/apollo-intellij-plugin/4.0.0-alpha.3-SNAPSHOT.27/apollo-intellij-plugin-4.0.0-alpha.3-SNAPSHOT.27.zip"
-      version="4.0.0-alpha.3-SNAPSHOT.27">
-    <idea-version since-build="222" until-build="232.*"/>
+      url="https://repsy.io/mvn/bod/apollo-intellij-plugin/com/apollographql/apollo-intellij-plugin/4.0.0-alpha.4-SNAPSHOT.28/apollo-intellij-plugin-4.0.0-alpha.4-SNAPSHOT.28.zip"
+      version="4.0.0-alpha.4-SNAPSHOT.28">
+    <idea-version since-build="223" until-build="232.*"/>
     <name>Apollo GraphQL (Weekly Snapshots)</name>
   </plugin>
 </plugins>