[BEAM-13430] Remove jcenter which will no longer contain any updates.

[lukecwik]

See https://jfrog.com/blog/into-the-sunset-bintray-jcenter-gocenter-and-chartcenter/

There are already issues with spurious timeouts/failures so the sooner we can remove the better our build stability will be.

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ValidatesRunner compliance status (on master branch)

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---					---
Java
Python	---					---
XLang						---

Examples testing status on various runners

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---	---	---	---	---	---	---
Java	---		---	---	---	---	---
Python	---	---	---	---	---	---	---
XLang	---	---	---	---	---	---	---

Post-Commit SDK/Transform Integration Tests Status (on master branch)

Go	Java	Python

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website	Whitespace	Typescript
Non-portable
Portable	---			---	---	---

See .test-infra/jenkins/README for trigger phrase, status and link of all Jenkins jobs.

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI.

[lukecwik]

CC: @ahmedabu98

[codecov]

Codecov Report

Merging #16527 (f592d1d) into master (9d40a4c) will increase coverage by 37.28%.
The diff coverage is n/a.

@@ Coverage Diff @@## master #16527 +/- ##
===========================================
+ Coverage 46.32% 83.61% +37.28% 
===========================================
Files 201 452 +251 Lines 19733 62070 +42337 ===========================================
+ Hits 9142 51900 +42758 - Misses 9610 10170 +560 + Partials 981 0 -981 

Impacted Files	Coverage Δ
...ks/go/pkg/beam/core/runtime/coderx/coderx.shims.go
sdks/go/pkg/beam/util/harnessopts/sampler.go
...kg/beam/core/runtime/graphx/schema/logicaltypes.go
sdks/go/pkg/beam/util/starcgenx/starcgenx.go
sdks/go/pkg/beam/transforms/stats/stats.shims.go
sdks/go/pkg/beam/core/graph/coder/row.go
sdks/go/pkg/beam/io/filesystem/gcs/gcs.go
...kg/beam/core/runtime/xlangx/expansionx/download.go
sdks/go/pkg/beam/io/databaseio/mapper.go
sdks/go/pkg/beam/core/util/reflectx/calls.go
... and 643 more

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