upgrade vsce to 1.93.0

motivation: this also upgrades underscore, which Dependabot has
been sending us a security alert about (CVE-2021-23358)

Author: SethTisue

package.json

@@ -53,7 +53,7 @@
         "rimraf": "^3.0.2",
         "ts-node": "^9.0.0",
         "typescript": "^4.0.2",
-        "vsce": "^1.79.5",
+        "vsce": "^1.93.0",
         "vscode-tmgrammar-test": "0.0.10"
     },
     "scripts": {