Create github action

[MiniDigger]

# download
wget https://pilotfiber.dl.sourceforge.net/project/javadiff/javadiff/jdiff%201.1.0/jdiff-1.1.0.zip
unzip jdiff-1.1.0.zip
# gen xml for paper
wget https://papermc.io/repo/repository/maven-snapshots/com/destroystokyo/paper/paper-api/1.16.5-R0.1-SNAPSHOT/paper-api-1.16.5-R0.1-20210310.211847-127-sources.jar -O paper-sources.jar
unzip paper-sources.jar -d paper-sources
mkdir paper
javadoc -doclet jdiff.JDiff -docletpath jdiff-1.1.0/jdiff.jar -apiname Paper -apidir paper -sourcepath paper-sources io.papermc org.bukkit org.spigotmc com.destroystokyo
# gen xml for spigot
wget https://hub.spigotmc.org/nexus/service/local/repositories/snapshots/content/org/spigotmc/spigot-api/1.16.5-R0.1-SNAPSHOT/spigot-api-1.16.5-R0.1-20210308.215427-28-sources.jar -O spigot-sources.jar
unzip spigot-sources.jar -d spigot-sources
mkdir spigot
javadoc -doclet jdiff.JDiff -docletpath jdiff-1.1.0/jdiff.jar -apiname Spigot -apidir spigot -sourcepath spigot-sources org.bukkit org.spigotmc 
# diff
unzip jdiff-1.1.0/xerces.jar -d jdiff-1.1.0/xerces
javadoc -classpath jdiff-1.1.0/xerces/:jdiff-1.1.0/:jdiff-1.1.0/xerces.jar -doclet jdiff.JDiff -docletpath jdiff-1.1.0/jdiff.jar -oldapi Spigot -oldapidir spigot -newapi Paper -newapidir paper -javadocold https://hub.spigotmc.org/javadocs/bukkit/ -javadocnew https://papermc.io/javadocs/paper/1.16/ -doctitle "PAPER TEST" -stats -d output -sourcepath paper-sources io.papermc org.bukkit org.spigotmc com.destroystokyo

current issue: cp doesnt pick up xerces xml parser, so stuff doesnt work

[MiniDigger]

same error on java 8 on github actions, meh https://github.com/MiniDigger/paper-api-diff/runs/2087826919?check_suite_focus=true#step:4:3976