Removed Jackson dependency

[abhijeetshuklaoist]

Signed-off-by: Abhijeet Shukla abhijeetshuklaoist@gmail.com

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Fixes #506 ☕️

[codecov]

Codecov Report

Merging #508 (7585b9d) into master (1887932) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@ Coverage Diff @@ ## master #508 +/- ## ============================================ - Coverage 74.09% 74.06% -0.03%  + Complexity 1117 1116 -1  ============================================ Files 66 66 Lines 5883 5884 +1 Branches 723 724 +1 ============================================ - Hits 4359 4358 -1  Misses 1296 1296 - Partials 228 230 +2 

Impacted Files	Coverage Δ	Complexity Δ
...a/com/google/cloud/firestore/DocumentSnapshot.java	80.85% <0.00%> (-0.87%)	39.00% <0.00%> (ø%)
.../com/google/cloud/firestore/CustomClassMapper.java	76.68% <0.00%> (-0.17%)	110.00% <0.00%> (-1.00%)

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[schmidt-sebastian]

Another approach for this PR would be to simply drop the JSON parsing from the callsites. The JSON parser is only used in the Unit tests and it seems straightforward to replace its usage. Instead of:

 @Test public void primitiveDeserializeString() { StringBean bean = deserialize("{'value': 'foo'}", StringBean.class); assertEquals("foo", bean.value); ... 

We could just do:

 @Test public void primitiveDeserializeString() { StringBean bean = deserialize(map("value", "foo"), StringBean.class); // assertEquals("foo", bean.value); private static <T> T deserialize(Map<String, Object> value, Class<T> clazz) ... 

deserialize could also be:

 private static <T> T deserialize(Class<T> clazz, String key, Object value, Object ... moreKeysAndValues) ... 

Which would make the callsites even more concise.

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[abhijeetshuklaoist]

@googlebot I fixed it.