feat: kirby 3.7 adaption, download indicator

Author: mauricerenck

composer.json

@@ -24,7 +24,7 @@
         "webeweb/pexels-library": "^2.4"
     },
     "require-dev": {
-        "getkirby/cms": "^3.6",
+        "getkirby/cms": "^3.7",
         "phpunit/phpunit": "9.5"
     },
     "replace": {},
@@ -37,4 +37,4 @@
         "build-test-package": "git archive HEAD -o plugin.zip --worktree-attributes",
         "build-composer": "composer install --no-dev --optimize-autoloader"
     }
-}
+}