Expose the factory methods of MonitoredResource.

[songy23]

To make the unit tests of other libraries that depend on monitored-resource-utils easier to write.

[codecov-io]

Codecov Report

Merging #1250 into master will increase coverage by 0.42%.
The diff coverage is 33.33%.

@@             Coverage Diff              @@
##             master    #1250      +/-   ##
============================================
+ Coverage     82.06%   82.48%   +0.42%     
- Complexity     1241     1244       +3     
============================================
  Files           193      193              
  Lines          6044     6047       +3     
  Branches        560      560              
============================================
+ Hits           4960     4988      +28     
+ Misses          935      909      -26     
- Partials        149      150       +1

Impacted Files	Coverage Δ	Complexity Δ
...trib/monitoredresource/util/MonitoredResource.java	88.57% <33.33%> (+63.57%)	3 <0> (+1)	⬆️
...rter/stats/stackdriver/StackdriverExportUtils.java	81.53% <0%> (ø)	29% <0%> (ø)	⬇️
...ib/monitoredresource/util/AwsIdentityDocUtils.java	56.25% <0%> (+4.16%)	7% <0%> (+1%)	⬆️
...trib/monitoredresource/util/GcpMetadataConfig.java	68.18% <0%> (+13.63%)	5% <0%> (+1%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a6e0485...42b5fad. Read the comment docs.

[rghetia]

LGTM

[sebright2]

Could we continue hiding the no-arg factory methods, to reduce the size of the API? I also think that the no-arg methods could be confusing, because users might expect the factory methods in AutoValue classes to be deterministic, but these depend on the environment.

[songy23]

Make sense to me, done.

[songy23]

Thanks!