removed Octo.jl (doesn't have Project.toml in docs directory which is indicative of legacy Documenter, so we pin Documenter to 0.20, which doesn't work if absent in the depot).
removed Electron.jl since it takes 60 min to complete
fixed ReactionNetworkImporter test to reflect addition to DocumentationGeneratorRegistry
fix URL redirect error when relative path is specified in meta
Set Example.jl@0.5.3 to fallback docs since the Documenter version configured there is 0.20 doesn't seem to work with julia 1.8. Lets switch it back once we have new version of Example.jl
meta