BUILD: CI: move cygwin builds to Github Actions

builds on travis-ci fail because of
https://travis-ci.community/t/cygwin-issue-cygheap-base-mismatch-detected/5359
unfortunately, documentation does not help.

so, let us move builds to Github Actions.

also, remove deprecated "sudo" directive from .travis.yml

.github/workflows/windows-latest.yml

@@ -0,0 +1,20 @@
+# build status appears on https://github.com/haproxy/haproxy/actions
+
+name: windows-latest
+
+on: [push]
+
+jobs:
+  cygwin:
+
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: install prerequisites
+      run: choco install bash make libssl-devel cygwin-devel gcc-core libgcc1 binutils lua-devel libpcre-devel zlib-devel --source cygwin
+    - name: fake step
+      run: C:\\tools\\cygwin\\bin\\bash -lc 'pwd'
+    - name: build
+      run: C:\\tools\\cygwin\\bin\\bash -lc 'cd $OLDPWD && make TARGET=cygwin USE_ZLIB=1 USE_PCRE=1 USE_PCRE_JIT=1 USE_LUA=1 USE_OPENSSL=1 USE_THREAD=1 && ./haproxy -vv'
+

.travis.yml

@@ -1,6 +1,5 @@
 # build status appears on https://travis-ci.com/haproxy/haproxy
 
-sudo: required
 dist: bionic
 
 language: c
@@ -86,12 +85,6 @@ matrix:
     if: type != cron
     compiler: clang
     env: TARGET=osx FLAGS="USE_OPENSSL=1" OPENSSL_VERSION=1.1.1d
-#  - os: windows
-#    if: type == cron
-#    install:
-#      - choco install bash make libssl-devel cygwin-devel gcc-core libgcc1 binutils lua-devel libpcre-devel zlib-devel --source cygwin
-#    script:
-#      - C:\\tools\\cygwin\\bin\\bash -lc 'cd $OLDPWD && make TARGET=cygwin USE_ZLIB=1 USE_PCRE=1 USE_PCRE_JIT=1 USE_LUA=1 USE_OPENSSL=1 USE_THREAD=1 && ./haproxy -vv'
   - os: linux
     if: type == cron
     compiler: clang