Bump AspectJ to 1.9.7.M3, supporting Java 15+16

Also pull up the version property into the parent POM, in order to be
able to use it in ITs, too, similarly to the ErrorProne version.

Author: kriegaex

plexus-compilers/plexus-compiler-aspectj/pom.xml

@@ -13,10 +13,6 @@
   <name>Plexus AspectJ Compiler</name>
   <description>AspectJ Compiler support for Plexus Compiler component.</description>
 
-  <properties>
-    <aspectj.version>1.9.6</aspectj.version>
-  </properties>
-
   <dependencies>
     <dependency>
       <groupId>org.codehaus.plexus</groupId>

pom.xml

@@ -47,6 +47,7 @@
     <redirectTestOutputToFile>true</redirectTestOutputToFile>
     <project.build.outputTimestamp>2020-08-24T00:30:49Z</project.build.outputTimestamp>
     <junit.version>4.13.2</junit.version>
+    <aspectj.version>1.9.7.M3</aspectj.version>
     <errorprone.version>2.6.0</errorprone.version>
   </properties>