Fix stdio stream redirection on Julia 1.6.

Project.toml

@@ -1,6 +1,6 @@
 name = "TeeStreams"
 uuid = "c24d529b-c83e-40e0-9fc3-05832c05a0ba"
-version = "1.1.0"
+version = "1.1.1"
 
 [compat]
 julia = "1.5"

src/TeeStreams.jl

@@ -122,12 +122,23 @@ end
 
 # Adapted from Logging2.jl (MIT License: Copyright (c) 2020 Chris Foster)
 # https://github.com/JuliaLogging/Logging2.jl/blob/094eb6619aeaa8815585dbe7f33b4972f9a4ce6b/src/Logging2.jl#L12-L37
+
+if VERSION >= v"1.7.0-DEV.254"
     function (redirect_func::Base.RedirectStdStream)(f::Function, io::TeeStream)
         prev_stream =
             redirect_func.unix_fd == 1 ? stdout :
             redirect_func.unix_fd == 2 ? stderr :
             throw(ArgumentError("Can only redirect stdout and stderr to TeeStream."))
+        return _redirect_internal(f, io, redirect_func, prev_stream)
+    end
+else
+    Base.redirect_stdout(f::Function, io::TeeStream) =
+        _redirect_internal(f, io, redirect_stdout, stdout)
+    Base.redirect_stderr(f::Function, io::TeeStream) =
+        _redirect_internal(f, io, redirect_stderr, stderr)
+end
 
+function _redirect_internal(f, io, redirect_func, prev_stream)
     result = nothing
 
     rd, rw = redirect_func()