Re-enable two pending tests

Per the discussion in #3319 (comment),
these only temporarily needed to be marked `pending` until
#3327 was merged.

From the first thread it looks like the intent was to remove the
`pending` comment, but that accidentally got overlooked.

So this removes them, and then fixes the failures.

One test was straightforward change from method to hash value.

But the other was a logical change from expecting a raised error to
expecting no error. However, this has been true since this code was
originally committed (once #3327 was merged to make the test work):
https://github.com/dependabot/dependabot-core/pull/3319/files#r600526250

I considered removing it, but thought it didn't hurt to continue to keep
it in to ensure no regressions... it is a `bundler 2` test, so still
valid even after we drop support for `bundler 1`.

bundler/spec/dependabot/bundler/update_checker/version_resolver_spec.rb

@@ -173,8 +173,8 @@
 
         let(:dependency_files) { bundler_project_dependency_files("requires_bundler") }
 
-        pending "resolves version" do
-          expect(subject.version).to eq(Gem::Version.new("3.0.0"))
+        it "resolves version" do
+          expect(subject[:version]).to eq(Gem::Version.new("3.0.0"))
         end
       end
 
@@ -184,9 +184,8 @@
 
         let(:dependency_files) { bundler_project_dependency_files("requires_bundler") }
 
-        pending "raises a DependencyFileNotResolvable error" do
-          expect { subject }.
-            to raise_error(Dependabot::DependencyFileNotResolvable)
+        it "resolves version" do
+          expect(subject[:version]).to eq(Gem::Version.new("2.2.1"))
         end
       end