CHG: Update conanfile.txt for conan 2.0

conanfile.txt

 [requires]
 caosdb/[>=0.3.0-dev, include_prerelease=True]
 
-[build_requires]
+[test_requires]
 gtest/1.11.0
 
 [generators]
-cmake
+CMakeDeps
+CMakeToolchain
 
 [options]
-caosdb:build_acm=True
+caosdb*:build_acm=True
+
+[layout]
+cmake_layout
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