added caveat to documentation

[ackoch]

Unquoted username:password get misinterpreted by (Un*x) shells

Calling

aio-aem aem:upload -d -h https://author-pXXXX-eXXXX.adobeaemcloud.com -t /content/dam -c myuser:my()password foofolder

results on macos /Linux in creating a new shell command:

$ which aio-aem

aio-aem () {
        password foofolder
}

Which overrides the actual aio-aem command.