make prom-client a peer dependency, upgrade all packages, bump 5.0.0

package.json

@@ -1,6 +1,6 @@
 {
   "name": "express-prom-bundle",
-  "version": "4.3.0",
+  "version": "5.0.0",
   "description": "express middleware with popular prometheus metrics in one bundle",
   "main": "src/index.js",
   "keywords": [
@@ -18,20 +18,22 @@
   "license": "MIT",
   "dependencies": {
     "on-finished": "^2.3.0",
-    "prom-client": "~11.2.1",
     "url-value-parser": "^2.0.0"
   },
   "devDependencies": {
     "coveralls": "^3.0.2",
-    "eslint": "^5.3.0",
-    "express": "^4.16.3",
+    "eslint": "^5.11.0",
+    "express": "^4.16.4",
     "istanbul": "^0.4.5",
-    "jasme": "^5.2.0",
-    "koa": "^2.5.2",
-    "koa-connect": "^2.0.0",
-    "supertest": "^3.0.0",
+    "jasme": "^6.0.0",
+    "koa": "^2.6.2",
+    "koa-connect": "^2.0.1",
+    "supertest": "^3.3.0",
     "supertest-koa-agent": "^0.3.0"
   },
+  "peerDependencies": {
+    "prom-client": "^11.1.2"
+  },
   "repository": {
     "type": "git",
     "url": "https://github.com/jochen-schweizer/express-prom-bundle.git"