chore: Upgrade gatsby to latest minor version.

Author: rmariuzzo

package-lock.json

@@ -27,12 +27,12 @@
     "@fontsource/source-code-pro": "^4.5.0",
     "@fontsource/source-sans-pro": "^4.5.0",
     "date-fns": "^2.23.0",
-    "gatsby": "^3.12.0",
-    "gatsby-plugin-google-gtag": "^3.12.0",
-    "gatsby-plugin-manifest": "^3.12.0",
-    "gatsby-remark-prismjs": "^5.9.0",
-    "gatsby-source-filesystem": "^3.12.0",
-    "gatsby-transformer-remark": "^4.9.0",
+    "gatsby": "^3.15.0",
+    "gatsby-plugin-google-gtag": "^3.15.0",
+    "gatsby-plugin-manifest": "^3.15.0",
+    "gatsby-remark-prismjs": "^5.12.0",
+    "gatsby-source-filesystem": "^3.15.0",
+    "gatsby-transformer-remark": "^4.12.0",
     "normalize.css": "^8.0.1",
     "prismjs": "^1.24.1",
     "react": "^17.0.2",
@@ -45,9 +45,9 @@
     "@types/react-helmet": "^6.1.2",
     "@types/styled-components": "^5.1.12",
     "babel-plugin-styled-components": "^1.13.2",
-    "gatsby-cli": "^3.12.0",
-    "gatsby-plugin-styled-components": "^4.12.0",
-    "gatsby-plugin-typescript": "^3.12.0",
+    "gatsby-cli": "^3.15.0",
+    "gatsby-plugin-styled-components": "^4.15.0",
+    "gatsby-plugin-typescript": "^3.15.0",
     "gh-pages": "^3.2.3",
     "husky": "^7.0.1",
     "inquirer": "^8.1.2",