cirrus: Remove the golangci-lint test

Cirrus CI runs golangci-lint, which is often way too noisy with false
positives and irrelevant checks. Last one was errcheck on
http.ResponseWriter.Write, but there have been others before.

Disable it for now, since it doesn't add enough value to justify the
introduced friction.

.cirrus.yml

@@ -1,4 +1,3 @@
-
 # Configuration for https://cirrus-ci.org/
 
 env:
@@ -17,38 +16,3 @@ freebsd_task:
     pw useradd testing -m
   test_script: |
     su testing -c "go test ./..."
-
-# GolangCI linter.
-lint_task:
-  name: GolangCI Lint
-  container:
-    image: golangci/golangci-lint:latest
-  environment:
-    LINT_CONFIG: |
-      issues:
-        exclude:
-          - "Error return value of .(.*Errorf?). is not checked"
-          - "Error return value of .(.*SetDeadline). is not checked"
-          - "Error return value of .(.*ListenAndServe). is not checked"
-        exclude-rules:
-          - path: _test\.go
-            linters:
-              - errcheck
-          - linters:
-              - staticcheck
-            # SA1015: time.Tick leaks but it's ok on endless functions.
-            text: "SA1015:"
-        exclude-use-default: true
-  lint_config_file:
-    path: /tmp/lint.yml
-    variable_name: LINT_CONFIG
-  run_script: |
-    golangci-lint run -v --out-format json \
-      -c /tmp/lint.yml \
-      > lint-report.json
-  always:
-    golangci_artifacts:
-      path: lint-report.json
-      type: text/json
-      format: golangci
-