release update compatibility for drupal 9

.gitignore

+.idea
\ No newline at end of file

.idea/.gitignore

-# Default ignored files
-/workspace.xml

.idea/bg_img_field.iml

-<?xml version="1.0" encoding="UTF-8"?>
-<module type="WEB_MODULE" version="4">
-  <component name="NewModuleRootManager">
-    <content url="file://$MODULE_DIR$" />
-    <orderEntry type="inheritedJdk" />
-    <orderEntry type="sourceFolder" forTests="false" />
-  </component>
-</module>
\ No newline at end of file

.idea/misc.xml

-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="JavaScriptSettings">
-    <option name="languageLevel" value="ES6" />
-  </component>
-</project>
\ No newline at end of file

.idea/modules.xml

-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/.idea/bg_img_field.iml" filepath="$PROJECT_DIR$/.idea/bg_img_field.iml" />
-    </modules>
-  </component>
-</project>
\ No newline at end of file

.idea/vcs.xml

-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="$PROJECT_DIR$" vcs="Git" />
-  </component>
-</project>
\ No newline at end of file