Update .appveyor.yml

Guess we need one long line.

Author: rpavlik

.appveyor.yml

@@ -38,11 +38,5 @@ install:
 build_script:
 - cmd: >-
     call "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community\\VC\\Auxiliary\\Build\\%VCVARS%.bat" &&
-    cmake -GNinja -Bbuild -H. \
-      -DCMAKE_TOOLCHAIN_FILE=c:/tools/vcpkg/scripts/buildsystems/vcpkg.cmake \
-      -DBUILD_TESTING=OFF \
-      -DCMAKE_BUILD_TYPE=Release \
-      -DPYTHON_EXECUTABLE=C:/Python37-x64/python.exe \
-      -DCMAKE_PREFIX_PATH=C:/Libraries/boost_%BOOST_VER%;C:/Tools/vcpkg/installed/%VCPKG_PLATFORM%;C:/projects \
-      -DVCPKG_TARGET_TRIPLET=%VCPKG_PLATFORM% &&
+    cmake -GNinja -Bbuild -H. -DCMAKE_TOOLCHAIN_FILE=c:/tools/vcpkg/scripts/buildsystems/vcpkg.cmake -DBUILD_TESTING=OFF -DCMAKE_BUILD_TYPE=Release -DPYTHON_EXECUTABLE=C:/Python37-x64/python.exe -DCMAKE_PREFIX_PATH=C:/Libraries/boost_%BOOST_VER%;C:/Tools/vcpkg/installed/%VCPKG_PLATFORM%;C:/projects -DVCPKG_TARGET_TRIPLET=%VCPKG_PLATFORM% &&
     ninja -C build