feat: suppress docs check for tests

.checkstyle/suppressions.xml

···
     "http://checkstyle.org/dtds/suppressions_1_2.dtd">
 <suppressions>
 
+    <!-- don't require docs for tests -->
+    <suppress files="{{PROJECT_NAME}}-(api)[\\/]src[\\/]test[\\/]java[\\/].*"
+              checks="(MissingJavadoc.*)"/>
+
 </suppressions>

.scripts/rename-template.sh

···
   "$REPO_ROOT/build-logic/src/main/kotlin/publishing-conventions.gradle.kts"
   "$REPO_ROOT/license.txt"
   "$REPO_ROOT/license_header.txt"
+  "$REPO_ROOT/.checkstyle/suppressions.xml"
 )
 
 if [[ -d "$SOURCE_MODULE_DIR/src/main/java" ]]; then