[Build] Use consistent naming for configuration files

 * Files used to configure maven plugins are put into a `.<plugin-name>` folder.
 * Files used by travis are prefixed with `.travis` (travis does not support folders)

Author: mpkorstanje

.m2/travis-ci-toolchains.xml renamed to .travis-toolchains.xml

@@ -6,33 +6,33 @@ cache:
     - "$HOME/.m2"
 
 install:
-  - mvn install -DskipTests=true -DskipITs=true -Darchetype.test.skip=true -Dmaven.javadoc.skip=true -B -V --toolchains .m2/travis-ci-toolchains.xml
+  - mvn install -DskipTests=true -DskipITs=true -Darchetype.test.skip=true -Dmaven.javadoc.skip=true -B -V --toolchains .travis-toolchains.xml
 
 jobs:
   include:
     # 1.1 Semver check
     - stage: test
       jdk: openjdk11
-      script: mvn verify -Pcheck-semantic-version -DskipTests=true -DskipITs=true -Darchetype.test.skip=true --toolchains .m2/travis-ci-toolchains.xml
+      script: mvn verify -Pcheck-semantic-version -DskipTests=true -DskipITs=true -Darchetype.test.skip=true --toolchains .travis-toolchains.xml
       env: CHECK_SEMANTIC_VERSION=true
 
     # 1.2 Tests
     - stage: test
       jdk: openjdk11
-      script: mvn verify -P-spotless-apply --toolchains .m2/travis-ci-toolchains.xml
+      script: mvn verify -P-spotless-apply --toolchains .travis-toolchains.xml
       env: VERIFY=true
 
       # 1.3 Coverage
     - stage: test
       jdk: openjdk11
-      script: mvn jacoco:prepare-agent verify jacoco:report coveralls:report --toolchains .m2/travis-ci-toolchains.xml
+      script: mvn jacoco:prepare-agent verify jacoco:report coveralls:report --toolchains .travis-toolchains.xml
       env: COVERAGE=true
 
     # 1.4 Javadoc
     - jdk: openjdk11
       env: JAVADOC=true
       script:
-        - mvn javadoc:jar --toolchains .m2/travis-ci-toolchains.xml
+        - mvn javadoc:jar --toolchains .travis-toolchains.xml
 
 branches:
   only:

.travis.yml

@@ -28,12 +28,12 @@ update-compatibility:
 
 update-dependency-versions:
 	mvn versions:force-releases
-	mvn versions:update-properties -DallowMajorUpdates=false -Dmaven.version.rules="file://`pwd`/.m2/maven-version-rules.xml"
+	mvn versions:update-properties -DallowMajorUpdates=false -Dmaven.version.rules="file://`pwd`/.versions/rules.xml"
 .PHONY: update-dependency-versions
 
 update-major-dependency-versions:
 	mvn versions:force-releases
-	mvn versions:update-properties -DallowMajorUpdates=true -Dmaven.version.rules="file://`pwd`/.m2/maven-version-rules.xml"
+	mvn versions:update-properties -DallowMajorUpdates=true -Dmaven.version.rules="file://`pwd`/.versions/rules.xml"
 .PHONY: update-major-dependency-versions
 
 update-changelog: