chore(ci): remove drone configuration

.drone.yml

@@ -1,124 +0,0 @@
----
-kind: pipeline
-type: kubernetes
-name: linter
-
-clone:
-  disable: true
-
-steps:
-- name: clone
-  image: git.cryptic.systems/volker.raschek/git:1.4.0
-
-- name: markdown lint
-  commands:
-  - markdownlint *.md
-  image: git.cryptic.systems/volker.raschek/markdownlint:0.43.0
-  resources:
-    limits:
-      cpu: 150
-      memory: 150M
-
-- name: golangci lint
-  commands:
-  - golangci-lint run
-  image: docker.io/golangci/golangci-lint:v1.64.8-alpine
-  resources:
-    limits:
-      cpu: 500
-      memory: 1G
-
-- name: email-notification
-  environment:
-    SMTP_FROM_ADDRESS:
-      from_secret: smtp_from_address
-    SMTP_FROM_NAME:
-      from_secret: smtp_from_name
-    SMTP_HOST:
-      from_secret: smtp_host
-    SMTP_USERNAME:
-      from_secret: smtp_username
-    SMTP_PASSWORD:
-      from_secret: smtp_password
-  image: git.cryptic.systems/volker.raschek/drone-email:0.1.5
-  resources:
-    limits:
-      cpu: 150
-      memory: 150M
-  when:
-    status:
-    - changed
-    - failure
-
-trigger:
-  event:
-    exclude:
-    - tag
-
----
-kind: pipeline
-type: kubernetes
-name: unit-test-amd64
-
-clone:
-  disable: true
-
-depends_on:
-- linter
-
-node_selector:
-  kubernetes.io/arch: amd64
-
-steps:
-- name: clone
-  image: git.cryptic.systems/volker.raschek/git:1.4.0
-
-- name: unit-test
-  commands:
-  - go test -v ./...
-  image: docker.io/library/golang:1.24.1
-  resources:
-    limits:
-      cpu: 250
-      memory: 500M
-
-trigger:
-  event:
-    exclude:
-    - tag
-
----
-kind: pipeline
-type: docker
-name: unit-test-arm64
-
-clone:
-  disable: true
-
-depends_on:
-- linter
-
-# node_selector:
-#   kubernetes.io/arch: arm64
-
-platform:
-  os: linux
-  arch: arm64
-
-steps:
-- name: clone
-  image: git.cryptic.systems/volker.raschek/git:1.4.0
-
-- name: unit-test
-  commands:
-  - go test -v ./...
-  image: docker.io/library/golang:1.24.1
-  # resources:
-  #   limits:
-  #     cpu: 250
-  #     memory: 500M
-
-trigger:
-  event:
-    exclude:
-    - tag