Revert "fix(deps): update dependency com.google.cloud:google-cloud-monitoring-parent to v3.4.2 (googleapis#8291)"

This reverts commit 1c6a84a.

Author: suztomo

java-monitoring/google-cloud-monitoring/pom.xml

@@ -11,7 +11,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-monitoring-parent</artifactId>
-    <version>3.4.2</version><!-- {x-version-update:google-cloud-monitoring:current} -->
+    <version>3.4.2-SNAPSHOT</version><!-- {x-version-update:google-cloud-monitoring:current} -->
   </parent>
   <properties>
     <site.installationModule>google-cloud-monitoring</site.installationModule>

java-monitoring/grpc-google-cloud-monitoring-v3/pom.xml

@@ -10,7 +10,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-monitoring-parent</artifactId>
-    <version>3.4.2</version><!-- {x-version-update:google-cloud-monitoring:current} -->
+    <version>3.4.2-SNAPSHOT</version><!-- {x-version-update:google-cloud-monitoring:current} -->
   </parent>
   <dependencies>
     <dependency>

java-monitoring/proto-google-cloud-monitoring-v3/pom.xml

@@ -10,7 +10,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-monitoring-parent</artifactId>
-    <version>3.4.2</version><!-- {x-version-update:google-cloud-monitoring:current} -->
+    <version>3.4.2-SNAPSHOT</version><!-- {x-version-update:google-cloud-monitoring:current} -->
   </parent>
   <dependencies>
     <dependency>