chore(package): update dependencies to latest version

kyoto-art_news4discord:
- @types/jest: 25.2.3 -> 26.0.15
- @types/node: 13.13.14 -> 14.14.5
- @typescript-eslint/eslint-plugin: 2.34.0 -> 4.6.0
- @typescript-eslint/parser: 2.34.0 -> 4.6.0
- eslint: 6.8.0 -> 7.12.1
- jest: 25.5.4 -> 26.6.1
- prettier: 1.19.1 -> 2.1.2
- ts-jest: 25.5.1 -> 26.4.3
- ts-loader: 6.2.2 -> 8.0.7
- typescript: 3.9.7 -> 4.0.5
- webpack: 4.43.0 -> 5.2.0
- webpack-cli: 3.3.12 -> 4.1.0

package.json

@@ -1,23 +1,23 @@
 {
   "devDependencies": {
     "@types/google-apps-script": "^1.0.10",
-    "@types/jest": "^25.1.1",
-    "@types/node": "^13.13.4",
-    "@typescript-eslint/eslint-plugin": "^2.19.0",
-    "@typescript-eslint/parser": "^2.19.0",
+    "@types/jest": "^26.0.15",
+    "@types/node": "^14.14.5",
+    "@typescript-eslint/eslint-plugin": "^4.6.0",
+    "@typescript-eslint/parser": "^4.6.0",
     "cpx": "^1.5.0",
-    "eslint": "^6.8.0",
+    "eslint": "^7.12.1",
     "eslint-config-prettier": "^6.10.0",
     "eslint-plugin-prettier": "^3.1.2",
     "gas-webpack-plugin": "^1.0.2",
-    "jest": "^25.1.0",
-    "prettier": "^1.19.1",
+    "jest": "^26.6.1",
+    "prettier": "^2.1.2",
     "rimraf": "^3.0.1",
-    "ts-jest": "^25.2.0",
-    "ts-loader": "^6.2.1",
-    "typescript": "^3.7.5",
-    "webpack": "^4.41.5",
-    "webpack-cli": "^3.3.10",
+    "ts-jest": "^26.4.3",
+    "ts-loader": "^8.0.7",
+    "typescript": "^4.0.5",
+    "webpack": "^5.2.0",
+    "webpack-cli": "^4.1.0",
     "yarn.lock": "^0.0.1-security"
   },
   "scripts": {