v1.6.36-p3: Add version check for Alias target

Alias target PNG::PNG is only added if the CMake version installed is
greater or equal 3.11. Also fixed version check for 3.12 to not use
GREATER_EQUAL that was not introduced until version 3.7.

v1.6.26-p6: Add version check for Alias target

Alias target PNG::PNG is only added if the CMake version installed is
greater or equal 3.11.

v1.6.26-p5

CMake 3.11 required

v1.6.36-p2

Add PNG::PNG ALIAS target

v1.6.26-p4

Add PNG::PNG ALIAS target

v1.6.36-p1: Merge pull request #4 from khourig/hunter-1.6.36

No NEON for Travis iOS builds

v1.6.36-p0: Merge pull request #3 from khourig/hunter-1.6.36

Update to 1.6.36 and add CI

v1.6.26-p3

Fix WindowsStore build

v1.6.26-p2

Fix Visual Studio linker error

v1.6.26-p1

Add PNG_DISABLE_AWK option