Add .java-version (jenv) to .gitignore (#940)

diff --git a/.gitignore b/.gitignore
index 333dfc0..fd46be4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,6 +23,7 @@
 .factorypath
 .mypy_cache
 .python-version
+.java-version
 .coverage
 vendor
 composer.lock