Move PrettyTables to [weakdeps] and bump 3.1.4

[Drvi]

This fixes an error I was getting on Julia 1.10:

(@v1.10) pkg> activate --shared snoop_compile
  Activating new project at `~/.julia/environments/snoop_compile`

(@snoop_compile) pkg> add SnoopCompile@3.1.3
   Resolving package versions...
    Updating `~/.julia/environments/snoop_compile/Project.toml`
ERROR: KeyError: key "PrettyTables" not found
Stacktrace:
  [1] getindex
    @ ./dict.jl:498 [inlined]
...

[Drvi]

Oh right, I made this on top of the 3.1.3 tag and it has conflicts with the master branch... @timholy could you please create a branch for the 3.1 version so I can target it? Thank you!

[timholy]

Done, see the release-3.1 branch

[Drvi]

Done! Thank you

[timholy]

JuliaRegistries/General#139144