Increased minimum Maven version to 3.5.4 (#573)

For compatibility with `flatten-maven-plugin`.

.github/workflows/maven-build.yml

@@ -10,10 +10,10 @@
 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 # copies of the Software, and to permit persons to whom the Software is
 # furnished to do so, subject to the following conditions:
-# 
+#
 # The above copyright notice and this permission notice shall be included in
 # all copies or substantial portions of the Software.
-# 
+#
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -39,7 +39,7 @@ jobs:
     strategy:
       matrix:
         maven-version:
-          - '3.3.9'
+          - '3.5.4'
           - '3.8.6'
     steps:
       - name: Checkout

pom.xml

@@ -44,7 +44,7 @@
   <description>Maven plugin for the ktlint Kotlin linter.</description>
 
   <prerequisites>
-    <maven>3.3.9</maven>
+    <maven>3.5.4</maven>
   </prerequisites>
 
   <properties>
@@ -542,7 +542,7 @@
             <configuration>
               <rules>
                 <requireMavenVersion>
-                  <version>[3.3.9,3.9)</version>
+                  <version>[3.5.4,3.9)</version>
                 </requireMavenVersion>
                 <requireJavaVersion>
                   <version>[11,12)</version>