cmake fetchcontent_declare(12) examples

neocmakelsp/neocmakelsp assets_for_test/ast_test/nheko_test.cmake :529 

FetchContent_Declare(
    Olm
    GIT_REPOSITORY https://gitlab.matrix.org/matrix-org/olm.git
    GIT_TAG        3.2.12
)

neocmakelsp/neocmakelsp experiment_assets/nheko.cmake :529 

FetchContent_Declare(
	Olm
	GIT_REPOSITORY https://gitlab.matrix.org/matrix-org/olm.git
	GIT_TAG 3.2.12)

bytecodealliance/wasmtime crates/c-api/tests/CMakeLists.txt :2 

FetchContent_Declare(
  googletest
  URL https://github.com/google/googletest/archive/refs/tags/release-1.12.1.zip
)