build(deps): update dependency org.apache.maven.plugins:maven-compiler-plugin to v3.12.1 (#2761)

Author: renovate-bot

google-cloud-spanner-bom/pom.xml

@@ -105,7 +105,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.11.0</version>
+        <version>3.12.1</version>
         <configuration>
           <source>1.8</source>
           <target>1.8</target>

pom.xml

@@ -154,7 +154,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.11.0</version>
+        <version>3.12.1</version>
         <configuration>
           <source>1.8</source>
           <target>1.8</target>