Update boost-url sha1 and build type

More details on why the build type change is needed here in the yocto
recipe update.  This is essentially the same change:
https://github.com/openembedded/meta-openembedded/commit/5eb46e36a66836f6bbc8a0ffd54ae8a7c10a841f

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I41091f35762a9e9adf8c0b1ca0be87e7f791d2bc
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index ed8c3ee..81b1d5e 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -173,13 +173,9 @@
     ),
     # version from /meta-openembedded/meta-oe/recipes-devtools/boost-url/boost-url_git.bb
     "CPPAlliance/url": PackageDef(
-        rev="a56ae0df6d3078319755fbaa67822b4fa7fd352b",
-        build_type="cmake",
-        config_flags=[
-            "-DBOOST_URL_BUILD_EXAMPLES=OFF",
-            "-DBOOST_URL_BUILD_TESTS=OFF",
-            "-DBOOST_URL_STANDALONE=ON",
-        ],
+        rev="4f712ed69a04a344957d22efa5dc111b415b3aff",
+        build_type="custom",
+        build_steps=[f"cp -a include/** {prefix}/include/"],
     ),
     # valijson v0.4, which contains the nlohmann/json.hpp include fix:
     # 66262bafb82c ("Include nlohmann/json.hpp instead of json.hpp")