Switch to preshed v4

pyproject.toml

@@ -4,7 +4,7 @@ requires = [
  "cython>=0.25,<3.0",
  "murmurhash>=1.0.2,<1.1.0",
  "cymem>=2.0.2,<2.1.0",
- "preshed>=3.0.2,<3.1.0",
+ "preshed>=4.0.0,<4.1.0",
  "blis>=0.7.8,<0.8.0",
  "numpy>=1.15.0",
 ]

requirements.txt

@@ -1,7 +1,7 @@
 # Explosion-provided dependencies
 murmurhash>=1.0.2,<1.1.0
 cymem>=2.0.2,<2.1.0
-preshed>=3.0.2,<3.1.0
+preshed>=4.0.0,<4.1.0
 blis>=0.7.8,<0.8.0
 srsly>=2.4.0,<3.0.0
 wasabi>=0.8.1,<1.2.0

setup.cfg

@@ -34,15 +34,15 @@ setup_requires =
  numpy>=1.15.0
  # We also need our Cython packages here to compile against 
  cymem>=2.0.2,<2.1.0
- preshed>=3.0.2,<3.1.0
+ preshed>=4.0.0,<4.1.0
  murmurhash>=1.0.2,<1.1.0
  blis>=0.7.8,<0.8.0
 install_requires =
  # Explosion-provided dependencies
  blis>=0.7.8,<0.8.0
  murmurhash>=1.0.2,<1.1.0
  cymem>=2.0.2,<2.1.0
- preshed>=3.0.2,<3.1.0
+ preshed>=4.0.0,<4.1.0
  wasabi>=0.8.1,<1.2.0
  srsly>=2.4.0,<3.0.0
  catalogue>=2.0.4,<2.1.0

thinc/backends/numpy_ops.pyx

@@ -12,7 +12,6 @@ from libc.stdint cimport uint32_t, uint64_t
 from libc.string cimport memcpy
 from libc.math cimport isnan
 from cymem.cymem cimport Pool
-from preshed.maps cimport PreshMap
 from murmurhash.mrmr cimport hash64
 cimport numpy as np