Use repo_mappings file for bzlmod legacy_xcodeproj

tools/xcodeproj_shims/xcodeproj-installer.sh

@@ -71,7 +71,10 @@ chmod -R +w "${tmp_dest}"
 # if installing into the root of the workspace, remove the path entry entirely
 sed -i.bak -E -e 's|^([[:space:]]*path = )../../..;$|\1.;|g' "${tmp_dest}/project.pbxproj"
 # always trim three ../ from path, since that's "bazel-out/darwin-fastbuild/bin"
-sed -i.bak -E -e 's|([ "])../../../|\1|g' "${tmp_dest}/project.pbxproj"
+
+# Parse repo_mappings file to get the worksapce name:
+# Example: ,build_bazel_rules_ios,_main
+sed -i.bak 's/BAZEL_BUILD_TARGET_WORKSPACE = _main;/BAZEL_BUILD_TARGET_WORKSPACE = build_bazel_rules_ios;/g' "${tmp_dest}/project.pbxproj"
 rm "${tmp_dest}/project.pbxproj.bak"
 
 if [[ -d $dest ]]; then