Upgrade Mockito 4.0.0 -> 4.5.1 (#84)

See:
- https://github.com/mockito/mockito/releases/tag/v4.1.0
- https://github.com/mockito/mockito/releases/tag/v4.2.0
- https://github.com/mockito/mockito/releases/tag/v4.3.0
- https://github.com/mockito/mockito/releases/tag/v4.3.1
- https://github.com/mockito/mockito/releases/tag/v4.4.0
- https://github.com/mockito/mockito/releases/tag/v4.5.0
- https://github.com/mockito/mockito/releases/tag/v4.5.1
- mockito/mockito@v4.0.0...v4.5.1

pom.xml

@@ -136,7 +136,7 @@
         <version.hamcrest>2.2</version.hamcrest>
         <version.jdk>11</version.jdk>
         <version.maven>3.6.3</version.maven>
-        <version.mockito>4.0.0</version.mockito>
+        <version.mockito>4.5.1</version.mockito>
         <version.nopen-checker>1.0.1</version.nopen-checker>
         <version.nullaway>0.9.6</version.nullaway>
         <!-- XXX: Two other dependencies are potentially of interest: