Fixing remaining stub mypy issues + run check-stubs to CI

Author: sw23

.github/workflows/build.yml

@@ -68,7 +68,7 @@ jobs:
       run: MICROPY_CPYTHON3=python3.8 MICROPY_MICROPYTHON=../ports/unix/micropython_coverage ./run-tests -j1 --via-mpy -d basics float
       working-directory: tests
     - name: Stubs
-      run: make stubs -j2
+      run: make check-stubs -j2
     - uses: actions/upload-artifact@v2
       with:
         name: stubs

shared-bindings/ipaddress/IPv4Address.c

@@ -126,7 +126,7 @@ const mp_obj_property_t ipaddress_ipv4address_version_obj = {
               (mp_obj_t)&mp_const_none_obj},
 };
 
-//|     def __eq__(self, other: IPv4Address) -> bool:
+//|     def __eq__(self, other: object) -> bool:
 //|         """Two Address objects are equal if their addresses and address types are equal."""
 //|         ...
 //|

shared-bindings/socketpool/SocketPool.c

@@ -58,7 +58,7 @@ STATIC mp_obj_t socketpool_socketpool_make_new(const mp_obj_type_t *type, size_t
 }
 
 
-//|     def socket(self, family: int = AF_INET, type: int = SOCK_STREAM, proto: int = IPPROTO_TCP) -> None:
+//|     def socket(self, family: int, type: int, proto: int) -> socketpool.Socket:
 //|         """Create a new socket
 //|
 //|         :param ~int family: AF_INET or AF_INET6