We no longer carry an SRI hash for the toolchain, so flake
updating is no longer needed for toolchain changes.
Signed-off-by: David Anderson <danderson@tailscale.com>
Also removes the toolchain builds from flake.nix. For now the flake
build uses upstream Go 1.20, a followup change will switch it back to
our custom toolchain.
Updates tailscale/corp#9005
Signed-off-by: David Anderson <danderson@tailscale.com>
Also fixes the Go toolchain SRI hash from a7f05c6bb0,
it turns out I initialized the file with an SRI hash for an older
toolchain version, and because of the unique way fixed-output derivations
work in nix, nix didn't tell me about the mismatch because it just
cache-hit on the older toolchain and moved on. Sigh.
Updates #6845.
Signed-off-by: David Anderson <danderson@tailscale.com>