chore: group guava with other core dependencies

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Commits in this repo since last synth:
18c3a1b deps: update core dependencies (#40)
5205863 deps: update dependency com.google.truth:truth to v1.0.1 (#32)
2b6f04d deps: update core transport dependencies to v1.34.1 (#43)
bf58cba chore: release 1.13.0 (#39)
7f4bea4 fix: add support for WITH clauses (#42)
b368b84 feat: allow using existing OAuth token for JDBC connection (#37)
6cdfb75 chore: remove deprecated method (#38)
5957008 fix: allow dots and colons in project id (#36)

Log from Synthtool

synthtool > Executing /tmpfs/src/git/autosynth/working_repo/synth.py. .github/ISSUE_TEMPLATE/bug_report.md .github/ISSUE_TEMPLATE/feature_request.md .github/ISSUE_TEMPLATE/support_request.md .github/PULL_REQUEST_TEMPLATE.md .github/release-please.yml .kokoro/build.bat .kokoro/build.sh .kokoro/coerce_logs.sh .kokoro/common.cfg .kokoro/continuous/common.cfg .kokoro/continuous/dependencies.cfg .kokoro/continuous/integration.cfg .kokoro/continuous/java11.cfg .kokoro/continuous/java7.cfg .kokoro/continuous/java8-osx.cfg .kokoro/continuous/java8-win.cfg .kokoro/continuous/java8.cfg .kokoro/continuous/lint.cfg .kokoro/continuous/propose_release.cfg .kokoro/continuous/propose_release.sh .kokoro/continuous/samples.cfg .kokoro/dependencies.sh .kokoro/linkage-monitor.sh .kokoro/nightly/common.cfg .kokoro/nightly/dependencies.cfg .kokoro/nightly/integration.cfg .kokoro/nightly/java11.cfg .kokoro/nightly/java7.cfg .kokoro/nightly/java8-osx.cfg .kokoro/nightly/java8-win.cfg .kokoro/nightly/java8.cfg .kokoro/nightly/lint.cfg .kokoro/nightly/samples.cfg .kokoro/presubmit/clirr.cfg .kokoro/presubmit/common.cfg .kokoro/presubmit/dependencies.cfg .kokoro/presubmit/integration.cfg .kokoro/presubmit/java11.cfg .kokoro/presubmit/java7.cfg .kokoro/presubmit/java8-osx.cfg .kokoro/presubmit/java8-win.cfg .kokoro/presubmit/java8.cfg .kokoro/presubmit/linkage-monitor.cfg .kokoro/presubmit/lint.cfg .kokoro/presubmit/samples.cfg .kokoro/release/bump_snapshot.cfg .kokoro/release/bump_snapshot.sh .kokoro/release/common.cfg .kokoro/release/common.sh .kokoro/release/drop.cfg .kokoro/release/drop.sh .kokoro/release/promote.cfg .kokoro/release/promote.sh .kokoro/release/publish_javadoc.cfg .kokoro/release/publish_javadoc.sh .kokoro/release/snapshot.cfg .kokoro/release/snapshot.sh .kokoro/release/stage.cfg .kokoro/release/stage.sh .kokoro/trampoline.sh CODE_OF_CONDUCT.md CONTRIBUTING.md LICENSE README.md codecov.yaml java.header license-checks.xml renovate.json synthtool > Wrote metadata to synth.metadata. 

[codecov]

Codecov Report

Merging #44 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@ Coverage Diff @@ ## master #44 +/- ## ============================================ - Coverage 77.87% 77.83% -0.04%  + Complexity 1722 1721 -1  ============================================ Files 60 60 Lines 5866 5866 Branches 825 825 ============================================ - Hits 4568 4566 -2  - Misses 925 926 +1  - Partials 373 374 +1

Impacted Files	Coverage Δ	Complexity Δ
...oogle/cloud/spanner/jdbc/SingleUseTransaction.java	86% <0%> (-1%)	36% <0%> (-1%)

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