Bump plugin parent pom to 4.78

[imonteroperez]

Highlights

• Asking to bump JTH version to a newer version.
• Facing issues on testing ScriptApprovalLoadingTest.dynamicLoading under IPv6 I faced the following issue:

java.io.IOException: Jenkins process terminated prematurely with exit code 1
	at org.jvnet.hudson.test.RealJenkinsRule.startJenkins(RealJenkinsRule.java:777)
	at org.jvnet.hudson.test.RealJenkinsRule.then(RealJenkinsRule.java:658)
	at org.jvnet.hudson.test.RealJenkinsRule.then(RealJenkinsRule.java:651)
	at org.jenkinsci.plugins.scriptsecurity.scripts.ScriptApprovalLoadingTest.dynamicLoading(ScriptApprovalLoadingTest.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.jvnet.hudson.test.RealJenkinsRule$1.evaluate(RealJenkinsRule.java:487)
[...]
Caused by: java.io.IOException: Failed to bind to /127.0.0.1:0

• Missed [RealJenkinsRule] Switching hardcoded IPv4 address to loopback address jenkins-test-harness#712

Testing done

• Tested locally via PCT with the proposed bump and working as expected

Submitter checklist

Beta Give feedback

1. Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
2. Ensure that the pull request title represents the desired changelog entry
3. Please describe what you did
4. Link to relevant issues in GitHub or Jira
5. Link to relevant pull requests, esp. upstream and downstream changes
6. Ensure you have provided tests - that demonstrates feature works or fixes the issue

[jglick]

#559 (comment)

[imonteroperez]

#559 (comment)

Addressed