Missing .gitignore just maven target

[nhojpatrick]

Without this .gitignore you'll see;

john@:~/forks/org.apache.commons/commons-logging (master) % git status
On branch master
Untracked files:
  (use "git add <file>..." to include in what will be committed)
	target/

nothing added to commit but untracked files present (use "git add" to track)
john@:~/forks/org.apache.commons/commons-logging (master) %

I have not added any user specific ignores, like IDE files as these should probably go in the users ~/.gitignore_global as they know what IDE they choose to use.

I've checked the build using mvn clean install -DskipTests but it fails with this error [ERROR] Failed to execute goal org.apache.maven.plugins:maven-jar-plugin:3.2.0:jar (apijar) on project commons-logging: You have to use a classifier to attach supplemental artifacts to the project instead of replacing them.. I've tried Java 1.6, 1.7 and 1.8 but I believe it is most likely due to the incorrect version of maven so a newer maven-jar-plugin being used. So the change I suggested regarding mvnw would have probably fixed this issue, as due to emails on the commons dev list the latest maven version should be used which I'm using.

[garydgregory]

Hi @nhojpatrick Please review git master to see if the recent commits match you needs and then possibly close this PR. TY!