New Puppet version somewhat changed error message, so update tests

spec/octocatalog-diff/integration/reference_validation_spec.rb

@@ -129,7 +129,7 @@ describe 'validation of references in computed catalog' do
     if OctocatalogDiff::Spec.is_puppet5?
       it 'should pass through the error messages from Puppet' do
         msg = @result.exception.message
-        expect(msg).to match(/Error: Could not find resource 'Exec\[subscribe target\]' in parameter 'subscribe' at/)
+        expect(msg).to match(/Error: Could not find resource 'Exec\[subscribe target\]' in parameter 'subscribe'/)
       end
     else
       # Multiple line numbers given because Puppet 4.x and 3.8 correspond to first and last line of resource, respectively.
@@ -162,7 +162,7 @@ describe 'validation of references in computed catalog' do
     if OctocatalogDiff::Spec.is_puppet5?
       it 'should pass through the error messages from Puppet' do
         msg = @result.exception.message
-        expect(msg).to match(/Error: Could not find resource 'Exec\[before target\]' in parameter 'before' at/)
+        expect(msg).to match(/Error: Could not find resource 'Exec\[before target\]' in parameter 'before'/)
       end
     else
       # rubocop:disable Metrics/LineLength
@@ -190,7 +190,7 @@ describe 'validation of references in computed catalog' do
     if OctocatalogDiff::Spec.is_puppet5?
       it 'should pass through the error messages from Puppet' do
         msg = @result.exception.message
-        expect(msg).to match(/Error: Could not find resource 'Test::Foo::Bar\[notify target\]' in parameter 'notify' at/)
+        expect(msg).to match(/Error: Could not find resource 'Test::Foo::Bar\[notify target\]' in parameter 'notify'/)
       end
     else
       # rubocop:disable Metrics/LineLength
@@ -218,7 +218,7 @@ describe 'validation of references in computed catalog' do
     if OctocatalogDiff::Spec.is_puppet5?
       it 'should pass through the error messages from Puppet' do
         msg = @result.exception.message
-        expect(msg).to match(/Error: Could not find resource 'Exec\[require target\]' in parameter 'require' at/)
+        expect(msg).to match(/Error: Could not find resource 'Exec\[require target\]' in parameter 'require'/)
       end
     else
       # rubocop:disable Metrics/LineLength
@@ -246,7 +246,7 @@ describe 'validation of references in computed catalog' do
 
       it 'should pass through the error messages from Puppet' do
         msg = @result.exception.message
-        expect(msg).to match(/Error: Could not find resource 'Exec\[subscribe target\]' in parameter 'subscribe' at/)
+        expect(msg).to match(/Error: Could not find resource 'Exec\[subscribe target\]' in parameter 'subscribe'/)
       end
     else
       it 'should succeed' do