Allow deploy to be skipped without failing the job

See merge request !14

Clean up extra directories

Closes #6

See merge request !13

If a runner is re-used, the presence of `TMP_DIR` will cause the script
to fail. To be safe, we'll also remove `SVN_DIR` to prevent conflicts,
even though the directories are timestamped.

Fixes #6

Update README

Closes #4 and #5

See merge request !12

Fixes #4
Fixes #5

Add static-assets directory to ignore list

Closes #2

See merge request !11

Fixes #2

Trigger static-asset cleanup by ensuring directory exists, even when empty

See merge request !10

Fix tag updates

Closes #3

See merge request !9

svn lacks a rename/replace function, requiring first that an existing
tag be deleted before an update is copied into place. svn is, fortunately,
generally smart enough to sort out the history and show only the updated
files in the resulting commit.

Support tag updates

See merge request !8

Add support for WP.org's static assets

See merge request !7

Support updates to existing tags

See merge request !6

Base image now provides rsync

See merge request !5

Explain gitattributes

See merge request !4

Fix readme typo

See merge request !3

Include release ref in info output

See merge request !2

Add CI badge

See merge request !1