.gitignore: .vscode/ipch directory
.gitignore: .vscode/ipch directory

It seems an update has started make these C++ extension PCH files show up in version control.

Change-Id: I9af5dbf7e74bf8fb7d9ef25e84cce28b7424dda8
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/27771
Presubmit-Ready: Ben Clayton <1f693eb7158dc33015048c09d6712f74dabddf79@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Tested-by: Ben Clayton <1c30fb039d402617778c76319a108b9f869da3ef@gmail.com>
Kokoro-Presubmit: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader