Update dependency semver to v7 (#21)

* Update document site

* Update dependency semver to v7

Co-authored-by: yosuke ota <[email protected]>
Co-authored-by: Renovate Bot <[email protected]>

Author: 3 people

package.json

@@ -34,7 +34,7 @@
     "nyc": "^15.0.0",
     "opener": "^1.5.1",
     "rimraf": "^3.0.0",
-    "semver": "^6.3.0",
+    "semver": "^7.0.0",
     "typescript": "^4.1.2",
     "vue-eslint-editor": "^1.1.0",
     "vue-eslint-parser": "^8.3.0",