fix: upgrade @mui/material from 5.15.16 to 5.15.19 (#134)

Snyk has created this PR to upgrade @mui/material from 5.15.16 to 5.15.19.

See this package in npm:
@mui/material

See this project in Snyk:
https://app.snyk.io/org/leachjustin18/project/6cc6e514-cb69-47cc-92cd-c501c9223429?utm_source=github&utm_medium=referral&page=upgrade-pr

Co-authored-by: snyk-bot <snyk-bot@snyk.io>

package.json

@@ -21,7 +21,7 @@
     "@emotion/react": "11.11.4",
     "@emotion/server": "11.11.0",
     "@emotion/styled": "11.11.5",
-    "@mui/material": "5.15.16",
+    "@mui/material": "5.15.19",
     "@mui/icons-material": "5.15.16",
     "date-fns": "^2.30.0",
     "gatsby": "^5.13.6",