fix: upgrade igv from 2.10.4 to 2.15.8

Snyk has created this PR to upgrade igv from 2.10.4 to 2.15.8.

See this package in npm:
https://www.npmjs.com/package/igv

See this project in Snyk:
https://app.snyk.io/org/grosscol/project/14486611-f583-41e7-968c-0fff2307a69f?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -25,7 +25,7 @@
     "core-js": "^3.6.5",
     "d3": "^7.1.1",
     "devbridge-autocomplete": "^1.4.11",
-    "igv": "^2.10.4",
+    "igv": "^2.15.8",
     "just-clone": "^3.2.1",
     "sinon": "^14.0.2",
     "tabulator-tables": "^4.9.3",