Add function for uploading a wiki attachment

mentioned in merge request gitlab-org/release-tools!3937 (merged)

mentioned in merge request gitlab-com/gl-infra/oncall-robot-assistant!79 (merged)

mentioned in merge request gitlab-com/gl-infra/autolabels!22 (merged)

mentioned in merge request gitlab-com/gl-infra/ringctl!248 (merged)

mentioned in merge request gitlab-com/gl-infra/platform/runway/runwayctl!866 (merged)

mentioned in merge request sue445/tanuki_reminder!226 (merged)

mentioned in merge request sue445/create-merge-request!108 (merged)

mentioned in merge request gitlab-org/cli!1946 (closed)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2348 (closed)

mentioned in merge request ydkn/gitlab-runner-cleanup!33 (closed)

mentioned in merge request gitlab-org/container-registry!2123 (merged)

mentioned in merge request gitlab-com/content-sites/handbook-tools/hugolint!123 (merged)

mentioned in merge request !2193 (merged)

mentioned in merge request !2265 (merged)