Remove obsolete PyCall dependency (#393)

Author: kojix2

.github/workflows/ci.yml

@@ -96,7 +96,6 @@ jobs:
 
       - name: Run tests
         env:
-          PYTHON: python
           ADAPTERS: cztop ffi-rzmq
         run: |
           for adapter in $ADAPTERS; do

iruby.gemspec

@@ -24,7 +24,6 @@ Gem::Specification.new do |s|
   s.add_dependency 'logger'
   s.add_dependency 'mime-types', '>= 3.3.1'
 
-  s.add_development_dependency 'pycall', '>= 1.2.1'
   s.add_development_dependency 'rake'
   s.add_development_dependency 'test-unit'
   s.add_development_dependency 'test-unit-rr'