Remove workaround for non-https builds.archive.org repository

It's now accessible over HTTPS, so we don't need this anymore.

.github/workflows/m2-settings.xml

@@ -1,14 +0,0 @@
-<settings xmlns="http://maven.apache.org/SETTINGS/1.2.0"
-          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.2.0 http://maven.apache.org/xsd/settings-1.2.0.xsd">
-    <mirrors>
-        <!-- unblock builds.archive.org mirror as it doesn't support https :-( -->
-        <mirror>
-            <id>builds.archive.org,maven2,mirror</id>
-            <mirrorOf>builds.archive.org,maven2</mirrorOf>
-            <name>builds.archive.org,maven2,mirror</name>
-            <url>http://builds.archive.org/maven2</url>
-            <blocked>false</blocked>
-        </mirror>
-    </mirrors>
-</settings>

.github/workflows/maven.yml

@@ -29,7 +29,7 @@ jobs:
         restore-keys: |
           ${{ runner.os }}-maven-
     - name: Build with Maven
-      run: mvn --settings .github/workflows/m2-settings.xml -B package --file pom.xml
+      run: mvn -B package --file pom.xml
       env:
         # Apparently Azure kills idle http connections after 4 minutes which can cause the build to fail
         # with a timeout error. Limit the connection ttl to 2 minutes to workaround this as per