Update dependency react-bootstrap to v2

Author: renovate[bot]

package.json

@@ -33,7 +33,7 @@
     "gatsby-source-published-google-sheets": "1.0.2",
     "normalize.css": "8.0.1",
     "react": "16.7.0",
-    "react-bootstrap": "^1.0.0-beta.6",
+    "react-bootstrap": "^2.0.0",
     "react-dom": "16.7.0",
     "react-emotion": "9.2.12",
     "react-hamburger-menu": "^1.1.1",