ci: exclude unpublished store URLs from link checker

The Marketplace and Open VSX extension pages return 404 until the
first publish. Exclude them from lychee to unblock CI on the prep
PR. Remove the exclusions after the first successful publish.

Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>

Author: SebTardif

lychee.toml

@@ -10,4 +10,8 @@ timeout = 30
 # Max concurrent requests
 max_concurrency = 4
 
-
+# Exclude store URLs that return 404 until first publish
+exclude = [
+  "https://marketplace.visualstudio.com/items\\?itemName=patchloom\\.patchloom",
+  "https://open-vsx.org/extension/patchloom/patchloom",
+]