Compose docs not deploying

[Mattriks]

@bjarthur The docs didn't deploy e.g. from #409.

Github actions shows:

┌ Info: Deployment criteria for deploying devbranch build from GitHub Actions:
│ - ✔ ENV["GITHUB_REPOSITORY"]="GiovineItalia/Compose.jl" occurs in repo="github.com/GiovineItalia/Compose.jl.git"
│ - ✔ ENV["GITHUB_EVENT_NAME"]="push" is "push"
│ - ✔ ENV["GITHUB_REF"] matches devbranch="master"
│ - ✔ ENV["GITHUB_ACTOR"] exists
│ - ✔ ENV["DOCUMENTER_KEY"] exists
└ Deploying: ✔
Initialized empty Git repository in /tmp/jl_ut5YeN/.git/
Failed to add the RSA host key for IP address '140.82.112.4' to the list of known hosts (/home/runner/.ssh/known_hosts).
Load key "/home/runner/work/Compose.jl/Compose.jl/docs/.documenter": invalid format
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
┌ Error: Git failed to fetch git@github.com:GiovineItalia/Compose.jl.git
│ This can be caused by a DOCUMENTER_KEY variable that is not correctly set up.
│ Make sure that the environment variable is properly set up as a Base64-encoded string
│ of the SSH private key. You may need to re-generate the keys with DocumenterTools.
└ @ Documenter ~/.julia/packages/Documenter/FuXcO/src/Documenter.jl:554

[bjarthur]

i created a new ssh key and secret. there error now is:

┌ Info: Deployment criteria for deploying preview build from GitHub Actions:
│ - ✔ ENV["GITHUB_REPOSITORY"]="GiovineItalia/Compose.jl" occurs in repo="github.com/GiovineItalia/Compose.jl.git"
│ - ✔ ENV["GITHUB_REF"] corresponds to a PR number
│ - ✘ `push_preview` keyword argument to deploydocs is `true`
│ - ✔ ENV["GITHUB_ACTOR"] exists
│ - ✔ ENV["DOCUMENTER_KEY"] exists
└ Deploying: ✘

[Mattriks]

Thanks! The Gadfly docs have been deploying when PRs -> master (e.g. from GiovineItalia/Gadfly.jl#1513), so let's see what happens with the next Compose PR?

[Mattriks]

After #415 was merged (actions link):

┌ Info: Deployment criteria for deploying devbranch build from GitHub Actions:
│ - ✔ ENV["GITHUB_REPOSITORY"]="GiovineItalia/Compose.jl" occurs in repo="github.com/GiovineItalia/Compose.jl.git"
│ - ✔ ENV["GITHUB_EVENT_NAME"]="push" is "push"
│ - ✔ ENV["GITHUB_REF"] matches devbranch="master"
│ - ✔ ENV["GITHUB_ACTOR"] exists
│ - ✔ ENV["DOCUMENTER_KEY"] exists
└ Deploying: ✔
┌ Error: Documenter failed to decode the DOCUMENTER_KEY environment variable.
│ Make sure that the environment variable is properly set up as a Base64-encoded string
│ of the SSH private key. You may need to re-generate the keys with DocumenterTools.
└ @ Documenter ~/.julia/packages/Documenter/FuXcO/src/Documenter.jl:630
ERROR: LoadError: ArgumentError: malformed base64 sequence