v1.8.0

Conda v1.8.0

Diff since v1.7.0

Closed issues:

• Conda.clean() fails because of --source-cache in generated call to conda (#218)
• How to Install Matplotlib using Conda.jl in Julia-1.7.3 (#222)
• libstdc++.so.6: version `GLIBCXX_3.4.30' not found (#224)
• GLIBCXX version problem with scipy.optimize on Linux (#226)
• Failing to install miniconda on Windows (#230)

Merged pull requests:

• rm --source-cache option from default clean (#219) (@stevengj)
• download installer to tempdir(), not installation dir (#231) (@stevengj)
• include Sys.ARCH in default rootenv (#232) (@stevengj)