POM File - Followup to "[maven-release-plugin] prepare for next development iteration". Update SCM tag.

Updated the value of the scm/tag element.

Looking at how it was before tagging release 1.0.1, it was "HEAD" here.
Using the branch name ("main") seems to be more correct.
diff --git a/pom.xml b/pom.xml
index 76c8cce..8da4004 100644
--- a/pom.xml
+++ b/pom.xml
@@ -102,7 +102,7 @@
     <connection>scm:git:https://gitbox.apache.org/repos/asf/tomcat-jakartaee-migration.git</connection>
     <developerConnection>scm:git:https://gitbox.apache.org/repos/asf/tomcat-jakartaee-migration.git</developerConnection>
     <url>https://gitbox.apache.org/repos/asf?p=tomcat-jakartaee-migration.git</url>
-    <tag>1.0.1</tag>
+    <tag>main</tag>
   </scm>
 
   <build>