bumped dev dependencies

Author: mtrezza

package.json

@@ -34,8 +34,8 @@
     "@babel/preset-env": "7.13.10",
     "codecov": "3.8.1",
     "babel-eslint": "10.1.0",
-    "eslint": "7.21.0",
-    "eslint-plugin-flowtype": "5.3.1",
+    "eslint": "7.22.0",
+    "eslint-plugin-flowtype": "5.4.0",
     "jasmine": "3.6.4",
     "nyc": "15.1.0",
     "mailgun.js": "3.2.1"