fix: move mongodb to peerDependencies (#435)

In order to allow `connect-mongo` to adapt to internal Typescript changes (that do not break the interface), we can specify `mongodb` as a peer dependency--allowing end users to use any version of mongodb they want as long as it's a minor release of driver version 4.1.x

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- Moved `mongodb` to a peer dependency (and also as a dev dependency for `connect-mongo` developers).  `connect-mongo` is no longer pinned to a specific version of `mongodb`.  This allows end users to avoid errors due to Typescript definition changes when moving to new versions of `mongodb`.  Users can use any version of `mongodb` that provides a compatible (non-breaking) interface to `mongodb ^4.1.0`.  Tested on `mongodb` `4.1.0` and `4.1.1`.  Should fix: [#433](https://github.com/jdesboeufs/connect-mongo/issues/433) [#434](https://github.com/jdesboeufs/connect-mongo/issues/434) [#436](https://github.com/jdesboeufs/connect-mongo/issues/436)
+
 ## [4.5.0] - 2021-08-17
 
 ### **BREAKING CHANGES**

package.json

@@ -56,16 +56,19 @@
   "engines": {
     "node": ">=10"
   },
+  "peerDependencies": {
+    "mongodb": "^4.1.0"
+  },
   "dependencies": {
     "debug": "^4.3.1",
-    "kruptein": "^3.0.0",
-    "mongodb": "4.1.0"
+    "kruptein": "^3.0.0"
   },
   "devDependencies": {
     "@ava/typescript": "^1.1.1",
     "@commitlint/cli": "^11.0.0",
     "@commitlint/config-conventional": "^11.0.0",
     "@istanbuljs/nyc-config-typescript": "^1.0.1",
+    "@types/debug": "^4.1.7",
     "@types/express": "^4.17.13",
     "@types/express-session": "^1.17.4",
     "@types/node": "^14.14.20",
@@ -91,6 +94,7 @@
     "gh-pages": "^3.1.0",
     "husky": "4",
     "lint-staged": "^10.5.4",
+    "mongodb": "^4.1.0",
     "npm-run-all": "^4.1.5",
     "nyc": "^15.1.0",
     "open-cli": "^6.0.1",