Drop support for Visual Studio 12 (2013) #1712

Job	Run time
Test CUDA support	31s
Test build-std (aarch64-tvos)	1m 29s
MSRV (ubuntu-latest)	27s
Clippy	9s
Test build-std (aarch64-tvos-sim)	1m 38s
Rustfmt	9s
MSRV (windows-latest)	44s
Test build-std (x86_64-tvos)	1m 32s
MSRV (macos-latest)	29s
semver-checks	14s
Test (stable)	21s
Test (beta)	27s
Test (nightly)	27s
Test (linux32)	1m 9s
Test (macos)	2m 24s
Test (aarch64-macos)	1m 31s
Test (aarch64-ios)	44s
Test (win32)	1m 8s
Test (win64)	2m 20s
Test (mingw32)	1m 27s
Test (mingw64)	1m 30s
Test (windows-2019)	1m 41s
Test (windows-aarch64, windows-latest, stable, aarch64-pc-windows-msvc, --no-run)	3m 2s
Test (windows-clang, windows-2019, stable, x86_64-pc-windows-msvc, clang, clang++)	2m 42s
Test (windows-clang-cl, windows-2019, stable, x86_64-pc-windows-msvc, clang-cl, clang-cl)	2m 32s
	30m 47s

Provide feedback