feat: add API for checker and support mod checking in update

[zong-zhe]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

2. What is the scope of this PR (e.g. component or file name):

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

[coveralls]

Pull Request Test Coverage Report for Build 12081312930

Details

• 53 of 97 (54.64%) changed or added relevant lines in 5 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.07%) to 41.096%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/client/check.go	17	31	54.84%
pkg/client/update.go	1	15	6.67%
pkg/checker/checker.go	14	30	46.67%

Files with Coverage Reduction	New Missed Lines	%
pkg/client/client.go	1	47.53%
pkg/checker/checker.go	2	71.05%

Totals
Change from base Build 12025056941:	-0.07%
Covered Lines:	3997
Relevant Lines:	9726

---

💛 - Coveralls

[He1pa]

lgtm