BREAKING CHANGE chore: upgrade to i18next v21 (#344)

* chore: upgrade to i18next v21

Even though the public API for aurelia-i18n does not change, i18next in v21.x introduces breaking changes that may bring surprises for aurelia users. Hence marking this as a BREAKING CHANGE. Major changes are:

- Plural suffix changed from `_plural` to `_other`.
- Missing interpolation variables are not replaced with empty string by default and you need to set the following initialization options: `interpolation: { skipOnVariables: false  }`

More details can be found here: https://www.i18next.com/misc/migration-guide#v20.x.x-to-v21.0.0.

* chore: additional deps update

Co-authored-by: Vildan Softic <zewa666@gmail.com>

package.json

@@ -114,7 +114,7 @@
       "aurelia-pal": "^1.8.2",
       "aurelia-templating": "^1.10.4",
       "aurelia-templating-resources": "^1.13.1",
-      "i18next": "^20.3.2"
+      "i18next": "^21.8.9"
     }
   },
   "dependencies": {
@@ -125,46 +125,46 @@
     "aurelia-logging": "^1.5.2",
     "aurelia-metadata": "^1.0.7",
     "aurelia-pal": "^1.8.2",
-    "aurelia-templating": "^1.10.4",
-    "aurelia-templating-resources": "^1.13.1"
+    "aurelia-templating": "^1.11.1",
+    "aurelia-templating-resources": "^1.14.3"
   },
   "peerDependencies": {
-    "i18next": ">=20.3.2"
+    "i18next": ">=21.8.9"
   },
   "devDependencies": {
     "@types/intl": "^1.2.0",
     "@types/jest": "^26.0.23",
-    "@types/node": "^16.0.0",
-    "@types/rimraf": "^3.0.0",
-    "@types/yargs": "^17.0.1",
-    "aurelia-bootstrapper": "^2.3.3",
+    "@types/node": "^17.0.42",
+    "@types/rimraf": "^3.0.2",
+    "@types/yargs": "^17.0.10",
+    "aurelia-bootstrapper": "^2.4.0",
     "aurelia-loader-nodejs": "^1.1.0",
     "aurelia-pal-browser": "^1.8.1",
     "aurelia-pal-nodejs": "^2.0.0",
     "aurelia-polyfills": "^1.3.4",
-    "aurelia-testing": "^1.0.0-beta.4.0.0",
-    "concurrently": "^6.2.0",
-    "conventional-changelog-cli": "^2.1.1",
+    "aurelia-testing": "^1.1.0",
+    "concurrently": "^7.2.1",
+    "conventional-changelog-cli": "^2.2.2",
     "copyfiles": "^2.4.1",
     "coveralls": "^3.1.1",
     "cross-env": "^7.0.3",
-    "dts-bundle-generator": "^5.9.0",
-    "full-icu": "^1.3.4",
+    "dts-bundle-generator": "^6.11.0",
+    "full-icu": "^1.4.0",
     "html-loader-jest": "^0.2.1",
-    "husky": "^7.0.0",
-    "i18next": "^20.3.2",
+    "husky": "^8.0.1",
+    "i18next": "^21.8.9",
     "identity-obj-proxy": "^3.0.0",
     "intl": "^1.2.5",
     "jest": "^27.0.6",
     "rimraf": "^3.0.2",
-    "rollup": "^2.52.7",
-    "rollup-plugin-typescript2": "^0.30.0",
+    "rollup": "^2.75.6",
+    "rollup-plugin-typescript2": "^0.32.1",
     "ts-jest": "^27.0.3",
-    "ts-node": "^10.0.0",
+    "ts-node": "^10.8.1",
     "tslint": "^6.1.3",
-    "typedoc": "^0.21.2",
-    "typescript": "^4.3.5",
-    "yargs": "^17.0.1"
+    "typedoc": "^0.22.17",
+    "typescript": "^4.7.3",
+    "yargs": "^17.5.1"
   },
   "aurelia": {
     "build": {