Migrate CI to use Github Actions (onnx#6075)

Migrate CI to use Github Actions. Update Google Test to a newer version
(some version in 2022). The latest commit has errors I don't know how to
fix.

Use `FetchContent` instead of `ExternalProject` to bring in googletest
according to its documentation
https://google.github.io/googletest/quickstart-cmake.html

Fixes onnx#6074 Fixes
onnx#6073

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Signed-off-by: Justin Chu <justinchu@microsoft.com>
Signed-off-by: Ganesan Ramalingam <grama@microsoft.com>