feat: hmac service account

[jkwlui]

Added the following Storage client methods:

• createHmacKey
• getHmacKeys
• hmacKey

HmacKey class and methods:

• get
• delete
• update

[codecov]

Codecov Report

Merging #751 into master will decrease coverage by 0.45%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #751      +/-   ##
==========================================
- Coverage   95.05%   94.59%   -0.46%     
==========================================
  Files          10       11       +1     
  Lines        1152     1202      +50     
  Branches      288      296       +8     
==========================================
+ Hits         1095     1137      +42     
- Misses         29       37       +8     
  Partials       28       28

Impacted Files	Coverage Δ
src/hmacKey.ts	100% <100%> (ø)
src/index.ts	100% <100%> (ø)	⬆️
src/storage.ts	99.1% <100%> (+0.4%)	⬆️
bin/benchwrapper.js	0% <0%> (ø)	⬆️

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[bcoe]

this is looking pretty lovely to me, on a quick read.

[bcoe]

looking fairly good to me, once tests are passing 😄

[frankyn]

Overall, looks good. I have two nit questions.

[frankyn]

@jkwlui could you add an optional parameter for projectId? This would help in the case the user doesn't want to use the project defined by credentials or GOOGLE_CLOUD_PROJECT.

[frankyn]

LGTM, thanks @jkwlui!

[stephenplusplus]

@jkwlui a new linty error has appeared, seemingly after I updated this PR to use the new common:

src/hmacKey.ts:323:7 - error TS2322: Type '{ delete: boolean; get: boolean; getMetadata: boolean; setMetadata: { reqOpts: { method: string; }; }; }' is not assignable to type 'Methods'.
  Property 'setMetadata' is incompatible with index signature.
    Type '{ reqOpts: { method: string; }; }' is not assignable to type 'boolean | { reqOpts?: CoreOptions | undefined; }'.
      Type '{ reqOpts: { method: string; }; }' is not assignable to type '{ reqOpts?: CoreOptions | undefined; }'.
        Types of property 'reqOpts' are incompatible.
          Type '{ method: string; }' is not assignable to type 'CoreOptions'.
            Types of property 'method' are incompatible.
              Type 'string' is not assignable to type '"GET" | "HEAD" | "POST" | "DELETE" | "PUT" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | undefined'.
323       methods,
          ~~~~~~~
  node_modules/@google-cloud/common/build/src/service-object.d.ts:54:5
    54     methods?: Methods;
           ~~~~~~~
    The expected type comes from property 'methods' which is declared here on type 'ServiceObjectConfig'

[jkwlui]

The tests are blocked by #818