docs: add UCloud as a production adopter

[allencloud]

Signed-off-by: Allen Sun [email protected]

Ⅰ. Describe what this PR did

We have heard from @Liberxue that UCloud is using PouchContainer to guarantee the disk quota for rocketmq in production environment, then I would like to put UCloud as an enterprise adopter of PouchContainer.

I would like to invite @Liberxue to introduce more production scenario about what you used PouchContainer. Could you help to introduce the following things:

• your demand about container solutions;
• why you have the demand;
• the solution PouchContainer provides;
• how you use PouchContainer;
• your further thoughts on PouchContainer

Thanks a lot if you are free to tell us your story.

Ⅱ. Does this pull request fix one issue?

none

Ⅲ. Why don't you add test cases (unit test/integration test)? (你真的觉得不需要加测试吗？)

no need

Ⅳ. Describe how to verify it

none

Ⅴ. Special notes for reviews

none

[codecov]

Codecov Report

Merging #2422 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2422      +/-   ##
==========================================
- Coverage   68.75%   68.75%   -0.01%     
==========================================
  Files         272      272              
  Lines       18159    18159              
==========================================
- Hits        12486    12485       -1     
- Misses       4253     4256       +3     
+ Partials     1420     1418       -2

Flag	Coverage Δ
#criv1alpha1test	31.51% <ø> (-0.02%)	⬇️
#criv1alpha2test	35.7% <ø> (+0.15%)	⬆️
#integrationtest	40.08% <ø> (-0.02%)	⬇️
#nodee2etest	32.88% <ø> (-0.01%)	⬇️
#unittest	26.52% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
daemon/mgr/snapshot.go	89.85% <0%> (-4.35%)	⬇️
apis/server/utils.go	71.15% <0%> (-3.85%)	⬇️
cri/v1alpha2/cri_utils.go	90.62% <0%> (-0.59%)	⬇️
cri/v1alpha2/cri_wrapper.go	62.4% <0%> (ø)	⬆️
daemon/mgr/container.go	59.22% <0%> (+0.21%)	⬆️
cri/v1alpha2/cri.go	68.04% <0%> (+0.24%)	⬆️
ctrd/container.go	59.28% <0%> (+0.39%)	⬆️
pkg/streams/utils.go	91.66% <0%> (+2.38%)	⬆️

[rudyfly]

LGTM