Update CI (jupyterlab#396)

* Update CI

* Add dev install script

* Automatic application of license header

* Add update snapshots workflow

* Update snapshots

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Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: 2 people

ui-tests/yarn.lock

@@ -2083,7 +2083,18 @@ __metadata:
   languageName: node
   linkType: hard
 
-"csstype@npm:3.0.10, csstype@npm:^3.0.2":
+"cross-spawn@npm:^7.0.0":
+  version: 7.0.5
+  resolution: "cross-spawn@npm:7.0.5"
+  dependencies:
+    path-key: ^3.1.0
+    shebang-command: ^2.0.0
+    which: ^2.0.1
+  checksum: 55c50004cb6bbea3649784caac6e7b8ddd03fa8c1e14dbd5a1f15896708378006eb7526a52a0f48770c768c9b8aed48a5888eb8e785ff59ff7749e74f66cd96b
+  languageName: node
+  linkType: hard
+
+"csstype@npm:3.0.10":
   version: 3.0.10
   resolution: "csstype@npm:3.0.10"
   checksum: 20a8fa324f2b33ddf94aa7507d1b6ab3daa6f3cc308888dc50126585d7952f2471de69b2dbe0635d1fdc31223fef8e070842691877e725caf456e2378685a631