chore(gitignore): also ignore debs*

GitHub Actions artifacts are called debs-<arch>-<commit>, can be
downloaded as zip, extracts to a folder of same name. which in turn
gives a deb folder which contains the actual deb files.

.gitignore

@@ -13,6 +13,9 @@ scripts/.vagrant/
 scripts/*.log
 /*.log
 
+# GitHub Actions build artifacts
+debs*
+
 # Built *.deb files.
 /debs/
 /output/