feat: support Gatsby v5 (#203)

* feat!: support Gatsby v5

These changes are needed for Gatsby v5 support.

* chore(deps): specify gatsby v4 as a peer dependency

* chore: revert minimum node version to 14 in order to continue to support Gatsby v4

Author: ericapisani

.nvmrc

@@ -0,0 +1 @@
+lts/hydrogen

package.json

@@ -45,7 +45,7 @@
   "license": "MIT",
   "main": "index.js",
   "peerDependencies": {
-    "gatsby": "^5.0.0"
+    "gatsby": "^4.0.0 || ^5.0.0"
   },
   "repository": {
     "type": "git",