The 'vendor' directory is included in git ignore, which makes sense.
Checked v1.5 and v1.6. The released ZIPs do not include the generated composer files.
Option A: include vendor directory in released packages
In addition, the README does not mention to run composer after unpacking the files and before activating the plugin in WordPress.
Option B: amend installation section in README
The 'vendor' directory is included in git ignore, which makes sense.
Checked v1.5 and v1.6. The released ZIPs do not include the generated composer files. Option A: include vendor directory in released packages
In addition, the README does not mention to run composer after unpacking the files and before activating the plugin in WordPress. Option B: amend installation section in README