[build] Remove unused 'immutable' and 'tree-kill' dependencies

Removing the unused dependencies left after merging the PR #3500

Signed-off-by: Victor Rubezhny <[email protected]>

package.json

@@ -78,7 +78,6 @@
 		"git-up": "^7.0.0",
 		"got": "^11.8.6",
 		"hasha": "^5.2.2",
-		"immutable": "^4.0.0",
 		"js-yaml": "^4.1.0",
 		"json-schema": "^0.4.0",
 		"lodash": "^4.17.21",
@@ -90,7 +89,6 @@
 		"stacktrace-parser": "^0.1.10",
 		"targz": "^1.0.1",
 		"tmp": "^0.2.1",
-		"tree-kill": "^1.2.2",
 		"unzip-stream": "^0.3.1",
 		"validator": "^13.11.0",
 		"vscode-kubernetes-tools-api": "^1.3.0",