Adjust GitHub actions windows build package list

Use the mingw-w64-x86_64 flavour of all packages.  Add curl, so
hfile_libcurl etc. build.  Remove the mingw git package as git
for windows is already present.  Add the location of git for
windows to $PATH (note this must be at the end, else the wrong
shell gets picked up when running tests leading to backslash
conversion issues).

Switch the badge on README.md from AppVeyor to GitHub.

.github/workflows/windows-build.yml

@@ -15,26 +15,26 @@ jobs:
         msystem: mingw64
         update: false
         install: >-
-          git
-          zlib-devel
-          libbz2-devel
-          liblzma-devel
-          mingw-w64-x86_64-toolchain
           mingw-w64-x86_64-autotools
-          mingw-w64-x86_64-tools-git
+          mingw-w64-x86_64-bzip2
+          mingw-w64-x86_64-curl
           mingw-w64-x86_64-libdeflate
+          mingw-w64-x86_64-toolchain
+          mingw-w64-x86_64-tools-git
+          mingw-w64-x86_64-xz
+          mingw-w64-x86_64-zlib
     - name: Compile htslib
       shell: msys2 {0}
       run: |
-        export PATH=/mingw64/bin:$PATH
+        export PATH="/mingw64/bin:$PATH:/c/Program Files/Git/bin"
         export MSYSTEM=MINGW64
         autoreconf -i
         ./configure
         make -j6
     - name: Check Htslib
       shell: msys2 {0}
       run: |
-        export PATH=/mingw64/bin:$PATH
+        export PATH="/mingw64/bin:$PATH:/c/Program Files/Git/bin"
         export MSYSTEM=MINGW64
         make test-shlib-exports && make check
 

README.md

@@ -1,5 +1,5 @@
 [![Build Status](https://api.cirrus-ci.com/github/samtools/htslib.svg?branch=develop)](https://api.cirrus-ci.com/github/samtools/htslib)
-[![Build status](https://ci.appveyor.com/api/projects/status/v46hkwyfjp3l8nd3/branch/develop?svg=true)](https://ci.appveyor.com/project/samtools/htslib/branch/develop)
+[![Build status](https://github.com/samtools/htslib/actions/workflows/windows-build.yml/badge.svg)](https://github.com/samtools/htslib/actions/workflows/windows-build.yml?query=branch%3Adevelop)
 [![Github All Releases](https://img.shields.io/github/downloads/samtools/htslib/total.svg)](https://github.com/samtools/htslib)
 
 HTSlib is an implementation of a unified C library for accessing common file