feat: Add support for workspace.dependencies in cargo 1.64.0+

I did not write tests because I don't know enough Ruby to do it, but I
will gladly accept directions on it.

Dockerfile

@@ -231,7 +231,7 @@ ENV RUSTUP_HOME=/opt/rust \
   PATH="${PATH}:/opt/rust/bin"
 RUN mkdir -p "$RUSTUP_HOME" && chown dependabot:dependabot "$RUSTUP_HOME"
 USER dependabot
-RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain 1.61.0 --profile minimal
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain 1.64.0 --profile minimal
 
 
 ### Terraform

cargo/lib/dependabot/cargo/file_parser.rb

@@ -79,6 +79,15 @@ def manifest_dependencies
               end
             end
           end
+
+          workspace = parsed_file(file).fetch("workspace", {})
+          workspace.fetch("dependencies", {}).each do |name, requirement|
+            next unless name == name_from_declaration(name, requirement)
+            next if lockfile && !version_from_lockfile(name, requirement)
+
+            dependency_set <<
+              build_dependency(name, requirement, "dependencies", file)
+          end
         end
 
         dependency_set