Update @types/pg to 8

Author: ThomWright

package-lock.json

@@ -55,7 +55,7 @@
   },
   "devDependencies": {
     "@types/node": "^10.17.60",
-    "@types/pg": "^7.14.11",
+    "@types/pg": "^8.6.0",
     "@types/sinon": "^9.0.11",
     "ava": "^3.15.0",
     "fit-commit-js": "^0.3.2",