Upgrade Guava by way of google-cloud-bom

[elefeint]

googleapis/google-cloud-java#3980 upgraded Guava (and gRPC/gax) and released version 0.71.

This should address the bulk of Snyk deserialization vulnerabilities.

[codecov-io]

Codecov Report

Merging #1233 into master will decrease coverage by 6.1%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1233      +/-   ##
============================================
- Coverage     73.54%   67.44%   -6.11%     
- Complexity     1275     1311      +36     
============================================
  Files           144      186      +42     
  Lines          4835     5381     +546     
  Branches        516      547      +31     
============================================
+ Hits           3556     3629      +73     
- Misses         1047     1520     +473     
  Partials        232      232

Flag	Coverage Δ	Complexity Δ
#integration	78.74% <ø> (?)	1584 <ø> (?)
#unittests	67.44% <ø> (-6.11%)	1311 <ø> (+36)

Impacted Files	Coverage Δ	Complexity Δ
...mple/src/main/java/com/example/SqlApplication.java	0% <0%> (ø)	0% <0%> (?)
...pubsub/provisioning/PubSubConsumerDestination.java	100% <0%> (ø)	2% <0%> (?)
...le/src/main/java/com/example/VisionController.java	0% <0%> (ø)	0% <0%> (?)
...r/src/main/java/com/example/SenderApplication.java	0% <0%> (ø)	0% <0%> (?)
...ream/binder/pubsub/PubSubMessageChannelBinder.java	81.25% <0%> (ø)	5% <0%> (?)
...-sample/src/main/java/com/example/SinkExample.java	0% <0%> (ø)	0% <0%> (?)
...n/java/com/example/DatastoreRepositoryExample.java	0% <0%> (ø)	0% <0%> (?)
...tastore-sample/src/main/java/com/example/Band.java	0% <0%> (ø)	0% <0%> (?)
...ple/src/main/java/com/example/HelloController.java	0% <0%> (ø)	0% <0%> (?)
...ub/properties/PubSubExtendedBindingProperties.java	100% <0%> (ø)	3% <0%> (?)
... and 32 more

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