Add and fix Ruby 3.1 and 3.2 to CI builds

Refactor .gitlab-ci.yml for parallel matrix builds and add caching for vendored gems.

rspec and rspec-parameterized gems had to be updated to make keyword argument matching work properly.

In addition, the spec needed to be updated so that Labkit::Tracing::Factory.create_tracer was passing in a Hash instead of keyword arguments.

spec/labkit/tracing/factory_spec.rb

@@ -32,7 +32,7 @@ describe Labkit::Tracing::Factory do
       end
 
       it "processes connections with parameters" do
-        expect(Labkit::Tracing::JaegerFactory).to receive(:create_tracer).with(service_name, a: "1", b: "2", c: "3").and_return(mock_tracer)
+        expect(Labkit::Tracing::JaegerFactory).to receive(:create_tracer).with(service_name, { a: "1", b: "2", c: "3" }).and_return(mock_tracer)
 
         expect(described_class.create_tracer(service_name, "opentracing://jaeger?a=1&b=2&c=3")).to be(mock_tracer)
       end
@@ -40,10 +40,12 @@ describe Labkit::Tracing::Factory do
       it "processes connections with basic auth credentials" do
         expect(Labkit::Tracing::JaegerFactory).to receive(:create_tracer).with(
           service_name,
-          a: "1",
-          b: "2",
-          c: "3",
-          http_endpoint: "https://foo:bar@observe.gitlab.com",
+          {
+            a: "1",
+            b: "2",
+            c: "3",
+            http_endpoint: "https://foo:bar@observe.gitlab.com",
+          }
         ).and_return(mock_tracer)
 
         expect(described_class.create_tracer(service_name, "opentracing://jaeger?http_endpoint=https://foo:bar@observe.gitlab.com&a=1&b=2&c=3")).to be(mock_tracer)