Enables unit-tests for the unevaluatedItems keyword.

[fdutton]

Resolves #748

[codecov-commenter]

Codecov Report

Merging #749 (b1b7dc8) into master (1d674ad) will decrease coverage by 0.44%.
The diff coverage is 68.80%.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

@@             Coverage Diff              @@
##             master     #749      +/-   ##
============================================
- Coverage     74.62%   74.19%   -0.44%     
- Complexity     1056     1066      +10     
============================================
  Files           110      111       +1     
  Lines          3673     3778     +105     
  Branches        708      721      +13     
============================================
+ Hits           2741     2803      +62     
- Misses          651      687      +36     
- Partials        281      288       +7     

Impacted Files	Coverage Δ
.../main/java/com/networknt/schema/JsonValidator.java	16.66% <0.00%> (-83.34%)	⬇️
...om/networknt/schema/UnevaluatedItemsValidator.java	0.00% <0.00%> (ø)
.../main/java/com/networknt/schema/Version202012.java	100.00% <ø> (ø)
...ava/com/networknt/schema/ItemsValidator202012.java	38.59% <47.36%> (+5.90%)	⬆️
...ava/com/networknt/schema/PrefixItemsValidator.java	38.88% <54.54%> (+6.23%)	⬆️
...main/java/com/networknt/schema/OneOfValidator.java	74.24% <63.63%> (+2.11%)	⬆️
...main/java/com/networknt/schema/ItemsValidator.java	75.24% <66.66%> (+1.09%)	⬆️
...c/main/java/com/networknt/schema/NotValidator.java	77.77% <70.00%> (+3.86%)	⬆️
...n/java/com/networknt/schema/ContainsValidator.java	76.92% <70.58%> (-0.86%)	⬇️
...rc/main/java/com/networknt/schema/IfValidator.java	87.14% <80.00%> (+3.21%)	⬆️
... and 6 more