Update Go Modules and Vendor Directory

[takumin]

CFSSL 1.6 supports the OID and E attributes of CSRs. I would like to use these attributes in my CA, but first I need to update the dependent CFSSL version in certmgr. Other than updating the vendor directory, the rest is small-scale, and the tests pass with Go 1.14, as shown below. Please let me know if there is anything else I need to do. Thanks a lot!

• Support E Attributes
  • https://github.com/cloudflare/cfssl/commit/9b27d0d80ebfdab86f3b54d64f194e726818d236
• Support OID Attributes
  • https://github.com/cloudflare/cfssl/commit/38b82406acc59d214d4d282d0dcb592a40770f52

 % make test
docker build . -f Dockerfile.test -t certmgr:test
[+] Building 1.2s (9/9) FINISHED
 => [internal] load build definition from Dockerfile.test                                                                                            0.0s
 => => transferring dockerfile: 43B                                                                                                                  0.0s
 => [internal] load .dockerignore                                                                                                                    0.1s
 => => transferring context: 2B                                                                                                                      0.0s
 => [internal] load metadata for docker.io/library/golang:1.14-stretch                                                                               0.8s
 => [1/4] FROM docker.io/library/golang:1.14-stretch@sha256:a60bc0c6be7e352336044e68db7089d8604864933fcbc0d7cb2285d60b0b2d98                         0.0s
 => [internal] load build context                                                                                                                    0.1s
 => => transferring context: 608.94kB                                                                                                                0.1s
 => CACHED [2/4] RUN mkdir -p /go/src/github.com/cloudflare/certmgr                                                                                  0.0s
 => CACHED [3/4] COPY . /go/src/github.com/cloudflare/certmgr/                                                                                       0.0s
 => CACHED [4/4] WORKDIR /go/src/github.com/cloudflare/certmgr                                                                                       0.0s
 => exporting to image                                                                                                                               0.1s
 => => exporting layers                                                                                                                              0.0s
 => => writing image sha256:fd6f0e2465fa1f9c2581cb66052bf21ef884951e9e8fd8801f4630f21cbf6bc7                                                         0.0s
 => => naming to docker.io/library/certmgr:test                                                                                                      0.0s
docker run -it certmgr:test /bin/bash
root@2b3c23356054:/go/src/github.com/cloudflare/certmgr# go test -mod=vendor -v ./...
=== RUN   TestCertificateMatchesHostname
--- PASS: TestCertificateMatchesHostname (0.00s)
PASS
ok      github.com/cloudflare/certmgr/cert      0.012s
=== RUN   TestFileBackend
=== RUN   TestFileBackend/just_ca
=== RUN   TestFileBackend/just_certs
=== RUN   TestFileBackend/all
=== RUN   TestFileBackend/missing_key
=== RUN   TestFileBackend/missing_cert
=== RUN   TestFileBackend/all_missing
=== RUN   TestFileBackend/reused_path1
=== RUN   TestFileBackend/reused_path2
=== RUN   TestFileBackend/reused_path3
--- PASS: TestFileBackend (0.00s)
    --- PASS: TestFileBackend/just_ca (0.00s)
    --- PASS: TestFileBackend/just_certs (0.00s)
    --- PASS: TestFileBackend/all (0.00s)
    --- PASS: TestFileBackend/missing_key (0.00s)
    --- PASS: TestFileBackend/missing_cert (0.00s)
    --- PASS: TestFileBackend/all_missing (0.00s)
    --- PASS: TestFileBackend/reused_path1 (0.00s)
    --- PASS: TestFileBackend/reused_path2 (0.00s)
    --- PASS: TestFileBackend/reused_path3 (0.00s)
PASS
ok      github.com/cloudflare/certmgr/cert/storage      0.003s
?       github.com/cloudflare/certmgr/cert/storage/util [no test files]
?       github.com/cloudflare/certmgr/certmgr   [no test files]
?       github.com/cloudflare/certmgr/certmgr/cmd       [no test files]
?       github.com/cloudflare/certmgr/certmgr/metrics   [no test files]
?       github.com/cloudflare/certmgr/certmgr/mgr       [no test files]