Update author of German translations

Shouldn’t really credit @jermolene, since it is actually @pmario who
has done the work.

languages/de-AT/plugin.info

@@ -3,8 +3,7 @@
 	"name": "de-AT",
 	"plugin-type": "language",
 	"description": "Deutsch (Österreich)",
-	"author": "JeremyRuston",
-	"maintainer": "MarioPietsch aka pmario",
+	"author": "MarioPietsch aka pmario",
 	"core-version": ">=5.0.0",
 	"dependents": ["$:/languages/de-DE"],
 	"plugin-priority": 110

languages/de-CH/plugin.info

@@ -3,7 +3,7 @@
 	"name": "de-CH",
 	"plugin-type": "language",
 	"description": "Deutsch (Schweiz)",
-	"author": "JeremyRuston",
+	"author": "MarioPietsch aka pmario",
 	"core-version": ">=5.0.0",
 	"dependents": ["$:/languages/de-DE"],
 	"plugin-priority": 110

languages/de-DE/plugin.info

@@ -3,8 +3,7 @@
 	"name": "de-DE",
 	"plugin-type": "language",
 	"description": "Deutsch (Deutschland)",
-	"author": "JeremyRuston",
-	"maintainer": "MarioPietsch aka pmario",
+	"author": "MarioPietsch aka pmario",
 	"core-version": ">=5.0.0",
 	"plugin-priority": 100
 }