Remove appveyor config (#2805)

This should be merged after #2804

Signed-off-by: Martin Kemp <me@martinke.mp>

appveyor.yml

@@ -1,60 +0,0 @@
-#---------------------------------#
-#      general configuration      #
-#---------------------------------#
-
-version: 1.0.{build}-{branch}
-
-# branches to build
-branches:
-  # blacklist
-  except:
-    - gh-pages
-
-#---------------------------------#
-#    environment configuration    #
-#---------------------------------#
-
-# Operating system (build VM template)
-os: Visual Studio 2022
-
-#---------------------------------#
-#       build configuration       #
-#---------------------------------#
-
-build_script:
-  - ps: cd scripts; .\build.ps1 -Compile -verbose
-
-after_build:
-  - ps: .\pack.ps1 -verbose
-
-# Disable test search, since we don't have any.
-test: off
-
-#---------------------------------#
-#           artifacts             #
-#---------------------------------#
-
-artifacts:
-  - path: build\cmder.zip
-    name: cmderzip
-
-  - path: build\cmder.7z
-    name: cmder7z
-
-  - path: build\cmder_mini.zip
-    name: cmdermini
-
-  - path: build\hashes.txt
-    name: hashes
-
-#---------------------------------#
-#         notifications           #
-#---------------------------------#
-
-notifications:
-  # Webhook
-  - provider: Webhook
-    url: https://webhooks.gitter.im/e/d673abb1b2e659dcd625
-    on_build_success: true
-    on_build_failure: true
-    on_build_status_changed: true