fix: make docker on master (inexistent docker alpine version)

[carloschida]

Currently when executing make docker on master, I get the following errors:

root@somewhere:~/kratos# make docker
DOCKER_BUILDKIT=1 docker build -f .docker/Dockerfile-build --build-arg=COMMIT=9097a60ede283fb2f6a912f2ab1ae1713d6598dd --build-arg=BUILD_DATE=2022-04-12T09:25:47Z -t oryd/kratos:latest .
[+] Building 2.0s (6/6) FINISHED                                                                                                                                                                                                                                         
 => [internal] load build definition from Dockerfile-build                                                                                                                                                                                                          0.0s
 => => transferring dockerfile: 38B                                                                                                                                                                                                                                 0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                                                   0.0s
 => => transferring context: 35B                                                                                                                                                                                                                                    0.0s
 => resolve image config for docker.io/docker/dockerfile:1-experimental                                                                                                                                                                                             0.7s
 => CACHED docker-image://docker.io/docker/dockerfile:1-experimental@sha256:600e5c62eedff338b3f7a0850beb7c05866e0ef27b2d2e8c02aa468e78496ff5                                                                                                                        0.0s
 => CANCELED [internal] load metadata for docker.io/library/alpine:3.15.4                                                                                                                                                                                           0.2s
 => ERROR [internal] load metadata for docker.io/library/golang:1.18-alpine3.15.4                                                                                                                                                                                   0.2s
------
 > [internal] load metadata for docker.io/library/golang:1.18-alpine3.15.4:
------
failed to solve with frontend dockerfile.v0: failed to solve with frontend gateway.v0: rpc error: code = Unknown desc = docker.io/library/golang:1.18-alpine3.15.4: not found

This is consistent with the fact that the tag doesn't exist on DockerHub.

The easy fix is to simply change the docker alpine version from 3.15.4 to 3.15.

Related issue(s)

None

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security. vulnerability, I
  confirm that I got green light (please contact
  security@ory.sh) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

[codecov]

Codecov Report

Merging #2390 (851c423) into master (b5b4ba7) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2390      +/-   ##
==========================================
- Coverage   76.61%   76.60%   -0.02%     
==========================================
  Files         315      315              
  Lines       17320    17320              
==========================================
- Hits        13270    13268       -2     
- Misses       3118     3119       +1     
- Partials      932      933       +1     

Impacted Files	Coverage Δ
persistence/sql/persister_courier.go	85.00% <0.00%> (-3.34%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9097a60...851c423. Read the comment docs.

[zepatrik]

Sorry for breaking this, was completely my fault.

[carloschida]

I see the problem better now. Docker tags are really confusing sometimes.
Waiting for the pipeline.

[zepatrik]

Thanks 👍