chore(instrumentation-mysql2): drop unneed @types/mysql2 dep (#1812)

Types are included in 'mysql2' now (as of some 2.x release).

The github:types/mysql2 dependency is problematic for dependabot version updates.
See: #1806 (comment)

Co-authored-by: Marc Pichler <[email protected]>

Author: trentm

package-lock.json

@@ -49,7 +49,6 @@
     "@opentelemetry/contrib-test-utils": "^0.34.3",
     "@opentelemetry/sdk-trace-base": "^1.8.0",
     "@types/mocha": "7.0.2",
-    "@types/mysql2": "github:types/mysql2",
     "@types/node": "18.6.5",
     "@types/semver": "7.5.3",
     "mocha": "7.2.0",