KeyError: key :load_dataset not found

The `key not found` error occurs when I _call_ any function in Seaborn.jl, which is quite weird.
```julia
julia> using Seaborn

julia> Seaborn.load_dataset
load_dataset (generic function with 1 method)

julia> Seaborn.load_dataset("tips")
ERROR: KeyError: key :load_dataset not found
Stacktrace:
[1] __getproperty(o::PyCall.PyObject, s::Symbol)
@ PyCall C:\Users\shuhu\.julia\packages\PyCall\BD546\src\PyCall.jl:307
[2] getproperty
@ C:\Users\shuhu\.julia\packages\PyCall\BD546\src\PyCall.jl:312 [inlined]
[3] load_dataset(name::String)
@ Seaborn C:\Users\shuhu\.julia\packages\Seaborn\vfmph\src\Seaborn.jl:754
[4] top-level scope
@ REPL[4]:1
```
Version info
```julia
(@v1.6) pkg> st
Status `C:\Users\shuhu\.julia\environments\v1.6\Project.toml`
[8f4d0f93] Conda v1.5.2
[7073ff75] IJulia v1.23.2
[5fb14364] OhMyREPL v0.5.10
[438e738f] PyCall v1.92.3
[d2ef9438] Seaborn v1.0.0
julia> versioninfo()
Julia Version 1.6.2
Commit 1b93d53fc4 (2021-07-14 15:36 UTC)
Platform Info:
OS: Windows (x86_64-w64-mingw32)
CPU: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-11.0.1 (ORCJIT, skylake)
Environment:
JULIA_NUM_THREADS = 8
```
`PyCall` info
```julia

julia> using PyCall

julia> PyCall.pyversion
v"3.8.3"

julia> PyCall.conda
true

# PyCall seems to work
julia> math = pyimport("math")
PyObject

julia> math.sin(math.pi / 4)
0.7071067811865476
```