releng: Add a legacy category.xml file for support of older targets

[bhufmann]

What it does

Add a legacy category.xml file for support of older targets
For example, 2021-06/e4.20 needs a different category.xml file due different name of json plugin.

How to test

Run build for 2021-06/e4.20 target in repo (use Java 17):

cp -f rcp/org.eclipse.tracecompass.rcp.product/legacy/tracing.product rcp/org.eclipse.tracecompass.rcp.product/
cp -f releng/org.eclipse.tracecompass.slf4j.binding.simple.properties/legacy/MANIFEST.MF releng/org.eclipse.tracecompass.slf4j.binding.simple.properties/META-INF
cp -f rcp/org.eclipse.tracecompass.rcp/legacy/feature.xml rcp/org.eclipse.tracecompass.rcp/
cp -f releng/org.eclipse.tracecompass.releng-site/legacy/category.xml releng/org.eclipse.tracecompass.releng-site/
mvn clean install -Dtarget-platform=tracecompass-e4.20 -Djdk.version=11 -Djdk.release=11 -Dtycho-use-project-settings=false -DskipTests=true -Dslf4j-bundle=org.slf4j.binding.simple -Dslf4j-version=1.7.30 -Drequired-maven-version=3.8 -Dtycho-version=2.7.5 -Dtycho-extras-version=2.7.5

Includes a commit to upgrade github artifacts to v4 in CI workflow in order to have a successful build.

Follow-ups

N/A

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the instructions in this template

Signed-off-by: Bernd Hufmann [email protected]