Add fix for Crashday Redline Edition (508980) (#70)

To avoid a black screen at startup set `FSAA `to `0` in `graphics.config`.

https://www.protondb.com/app/508980

protonfixes/gamefixes/508980.py

@@ -0,0 +1,23 @@
+""" Game fix for Crashday Redline Edition
+"""
+
+# pylint: disable=C0103
+
+import json
+from protonfixes import util
+
+
+def main():
+    """ Change setting FSAA to 0 in graphics.config
+    """
+
+    config = (util.protonprefix() + "drive_c/users/steamuser/Local Settings/" +
+              "Application Data/Crashday/config/graphics.config")
+
+    # https://stackoverflow.com/a/45435707
+    with open(config, 'r') as file:
+        json_data = json.load(file)
+        if 'FSAA' in json_data:
+            json_data['FSAA'] = 0
+    with open(config, 'w') as file:
+        json.dump(json_data, file, indent=4)