Bump actions/checkout from 2.3.5 to 2.4.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.5 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2.3.5...v2.4.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/maven.yml

@@ -31,7 +31,7 @@ jobs:
 #            experimental: true
         
     steps:
-    - uses: actions/checkout@v2.3.5
+    - uses: actions/checkout@v2.4.0
     - uses: actions/cache@v2.1.7
       with:
         path: ~/.m2/repository

src/changes/changes.xml

@@ -49,7 +49,7 @@
       <action                 type="update" dev="ggregory" due-to="Dependabot">Bump jmh-core from 1.32 to 1.33 #176.</action>
       <action                 type="update" dev="ggregory" due-to="Dependabot">Bump jmh-generator-annprocess from 1.32 to 1.33 #175.</action>
       <action                 type="update" dev="ggregory" due-to="Dependabot">Bump commons.pmd-impl.version from 6.36.0 to 6.40.0 #173, #189, #193.</action>
-      <action                 type="update" dev="ggregory" due-to="Dependabot">Bump actions/checkout from 2.3.4 to 2.3.5 #188.</action>
+      <action                 type="update" dev="ggregory" due-to="Dependabot">Bump actions/checkout from 2.3.4 to 2.4.0 #188, #195.</action>
       <action                 type="update" dev="ggregory" due-to="Dependabot">Bump mockito-core from 3.11.2 to 4.1.0 #187, #197.</action>
       <action                 type="update" dev="ggregory" due-to="Dependabot">Bump maven-pmd-plugin from 3.14.0 to 3.15.0 #184.</action>
       <action                 type="update" dev="ggregory" due-to="Gary Gregory">Bump opencsv from 5.5.1 to 5.5.2 #182.</action>