Allow VK_API_VERSION_1_2 in VkJson

... which just falls through to VK_API_VERSION_1_1.
SwiftShader has started to advertise 1.2 with aosp/1634282.

Bug: b/182850741
Test: cts -m CtsGraphicsTestCases -t android.graphics.cts.VulkanFeaturesTest
Change-Id: I9845eafb8fd4b3df196302d1e4b53809b80dc669