appveyor.yml: remove appveyor configuration (#34720)

Removes the appveyor.yml since we moved to github runners.

---------

Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>

appveyor.yml

@@ -1,39 +0,0 @@
-clone_depth: 5
-version: "{branch}.{build}"
-
-image:
-  - Visual Studio 2019
-
-environment:
-  matrix:
-    - GETH_ARCH: amd64
-      GETH_MINGW: 'C:\msys64\mingw64'
-    - GETH_ARCH: 386
-      GETH_MINGW: 'C:\msys64\mingw32'
-
-install:
-  - git submodule update --init --depth 1 --recursive
-  - go version
-
-for:
-  # Windows builds for amd64 + 386.
-  - matrix:
-      only:
-        - image: Visual Studio 2019
-    environment:
-      # We use gcc from MSYS2 because it is the most recent compiler version available on
-      # AppVeyor. Note: gcc.exe only works properly if the corresponding bin/ directory is
-      # contained in PATH.
-      GETH_CC: '%GETH_MINGW%\bin\gcc.exe'
-      PATH: '%GETH_MINGW%\bin;C:\Program Files (x86)\NSIS\;%PATH%'
-    build_script:
-      - 'echo %GETH_ARCH%'
-      - 'echo %GETH_CC%'
-      - '%GETH_CC% --version'
-      - go run build/ci.go install -dlgo -arch %GETH_ARCH% -cc %GETH_CC%
-    after_build:
-      # Upload builds. Note that ci.go makes this a no-op PR builds.
-      - go run build/ci.go archive -arch %GETH_ARCH% -type zip -signer WINDOWS_SIGNING_KEY -upload gethstore/builds
-      - go run build/ci.go nsis -arch %GETH_ARCH% -signer WINDOWS_SIGNING_KEY -upload gethstore/builds
-    test_script:
-      - go run build/ci.go test -dlgo -arch %GETH_ARCH% -cc %GETH_CC% -short