Bump chart.js from 2.7.3 to 2.8.0 (#2094)

Bumps [chart.js](https://github.com/chartjs/Chart.js) from 2.7.3 to 2.8.0.
- [Release notes](https://github.com/chartjs/Chart.js/releases)
- [Commits](https://github.com/chartjs/Chart.js/compare/v2.7.3...v2.8.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

package.json

@@ -88,7 +88,7 @@
     "@rails/webpacker": "^3.5.5",
     "babel-plugin-transform-react-jsx": "^6.24.1",
     "babel-preset-preact": "^1.1.0",
-    "chart.js": "^2.7.3",
+    "chart.js": "^2.8.0",
     "codemirror": "^5.44.0",
     "intersection-observer": "^0.5.1",
     "linkstate": "^1.1.1",

yarn.lock

@@ -2700,10 +2700,10 @@ chardet@^0.7.0:
   resolved "https://registry.yarnpkg.com/chardet/-/chardet-0.7.0.tgz#90094849f0937f2eedc2425d0d28a9e5f0cbad9e"
   integrity sha512-mT8iDcrh03qDGRRmoA2hmBJnxpllMR+0/0qlzjqZES6NdiWDcZkCNAk4rPFZ9Q85r27unkiNNg8ZOiwZXBHwcA==
 
-chart.js@^2.7.3:
-  version "2.7.3"
-  resolved "https://registry.yarnpkg.com/chart.js/-/chart.js-2.7.3.tgz#cdb61618830bf216dc887e2f7b1b3c228b73c57e"
-  integrity sha512-3+7k/DbR92m6BsMUYP6M0dMsMVZpMnwkUyNSAbqolHKsbIzH2Q4LWVEHHYq7v0fmEV8whXE0DrjANulw9j2K5g==
+chart.js@^2.8.0:
+  version "2.8.0"
+  resolved "https://registry.yarnpkg.com/chart.js/-/chart.js-2.8.0.tgz#b703b10d0f4ec5079eaefdcd6ca32dc8f826e0e9"
+  integrity sha512-Di3wUL4BFvqI5FB5K26aQ+hvWh8wnP9A3DWGvXHVkO13D3DSnaSsdZx29cXlEsYKVkn1E2az+ZYFS4t0zi8x0w==
   dependencies:
     chartjs-color "^2.1.0"
     moment "^2.10.2"