Include version in artifact filename.

Removes the "archive version" override for the `shadowJar` task in the
build file, resulting in a jar-file that contains the current version
number in the filename. It's mostly a convenience tradeoff; either we
can see the version directly in the filename and avoid assumptions, or
we can easily overwrite an existing jar-file with a new one.

Also updates the upload step of the build workflow to a glob pattern so
we grab the file regardless of the version.

.github/workflows/build.yml

@@ -26,4 +26,4 @@ jobs:
         uses: actions/upload-artifact@v3
         with:
           name: MobArena.jar
-          path: build/libs/MobArena.jar
+          path: build/libs/MobArena-*.jar

build.gradle.kts

@@ -58,7 +58,6 @@ tasks {
 
         archiveBaseName = "MobArena"
         archiveClassifier = ""
-        archiveVersion = ""
     }
 
     // We're using shadowJar, so we can skip the regular jar task.