add flatten-maven-plugin 1.7.0

[hboutemy]

https://github.com/jvm-repo-rebuild/reproducible-central/blob/master/content/org/codehaus/mojo/flatten-maven-plugin/README.md

[github-actions]

• org.codehaus.mojo:flatten-maven-plugin 1.7.0

./rebuild.sh content/org/codehaus/mojo/flatten-maven-plugin/flatten-maven-plugin-1.7.0.buildspec

version=1.7.0
ok=4
ko=0
ignored=0
koFiles=""
ignoredFiles=""
reference_java_version="21 (from MANIFEST.MF Build-Jdk-Spec)"
reference_os_name="Unix (from pom.properties newline)"

docker build -q -t ghcr.io/jvm-repo-rebuild/rb-ubuntu-jdk21-toolchains-21
	0:56.05 real,	0.17 user,	0.12 sys
docker build -q -t ghcr.io/jvm-repo-rebuild/rb-ubuntu-jdk21-toolchains-21-maven-3.9.1
	0:10.48 real,	0.08 user,	0.05 sys
docker build -q -t ghcr.io/jvm-repo-rebuild/rb-ubuntu-jdk21-toolchains-21-maven-3.9.1-runner
	0:13.66 real,	0.08 user,	0.06 sys
docker build -q -t ghcr.io/jvm-repo-rebuild/rb-ubuntu-jdk21-toolchains-21-maven-3.9.1-runner-utc-en_us-022
	0:17.47 real,	0.08 user,	0.07 sys
docker run --name rebuild-central --rm
	0:21.75 real,	0.00 user,	0.02 sys