switch back from golang.org/x/sys/execabs to os/exec (go1.19)

[thaJeztah]

• relates to Use golang.org/x/sys/execabs instead of os/exec #195

This reverts commit f2a5645, which switched from os/exec to the golang.org/x/sys/execabs package to mitigate security issues (mainly on Windows) with lookups resolving to binaries in the current directory.

from the go1.19 release notes https://go.dev/doc/go1.19#os-exec-path

PATH lookups

Command and LookPath no longer allow results from a PATH search to be found
relative to the current directory. This removes a common source of security
problems but may also break existing programs that depend on using, say,
exec.Command("prog") to run a binary named prog (or, on Windows, prog.exe) in
the current directory. See the os/exec package documentation for information
about how best to update such programs.

On Windows, Command and LookPath now respect the NoDefaultCurrentDirectoryInExePath
environment variable, making it possible to disable the default implicit search
of “.” in PATH lookups on Windows systems.

[thaJeztah]

cc @kevpar @helsaawy (I noticed that using the latest go-winio with current versions of go.. brought back this package as a dependency)

[thaJeztah]

oh! looks like it's coming back through golang.org/x/tools (v0.11.0 still uses it, as it's missing golang/tools@f60f2e6). In either case, it should be good to remove it as import 😅