Add benchstat action for PRs

[julienduchesne]

This will compare between PR and main

[github-actions]

Benchstat (compared to main):

name                                                                    old time/op  new time/op  delta
Definition/test_goto_definition_for_var_myvar-2                         5.89µs ± 8%  5.67µs ± 0%  -3.72%  (p=0.016 n=5+4)
Definition/test_goto_definition_on_function_helper-2                    5.55µs ± 3%  5.74µs ± 0%  +3.52%  (p=0.016 n=5+4)
Definition/test_goto_inner_definition-2                                 5.97µs ± 2%  5.85µs ± 0%  -1.96%  (p=0.008 n=5+5)
Definition/test_goto_super_index-2                                      5.69µs ± 6%  5.97µs ± 1%    ~     (p=0.151 n=5+5)
Definition/test_goto_super_nested-2                                     6.07µs ±20%  5.97µs ± 1%    ~     (p=0.690 n=5+5)
Definition/test_goto_self_object_field_function-2                       5.75µs ± 0%  6.13µs ± 1%  +6.67%  (p=0.008 n=5+5)
Definition/test_goto_super_object_field_local_defined_obj_'foo'-2       6.35µs ± 4%  6.37µs ± 0%    ~     (p=0.690 n=5+5)
Definition/test_goto_super_object_field_local_defined_obj_'g'-2         6.40µs ± 4%  6.46µs ± 0%    ~     (p=0.690 n=5+5)
Definition/test_goto_local_var_from_other_local_var-2                   5.02µs ± 6%  5.17µs ± 0%    ~     (p=0.151 n=5+5)
Definition/test_goto_local_obj_field_from_'self.attr'_from_other_obj-2  7.11µs ± 0%  7.56µs ± 0%  +6.20%  (p=0.008 n=5+5)
Definition/test_goto_local_object_'obj'_via_obj_index_'obj.foo'-2       5.85µs ± 4%  5.99µs ± 0%    ~     (p=0.635 n=5+5)
Definition/test_goto_imported_file-2                                    15.9µs ± 5%  16.4µs ± 1%    ~     (p=0.690 n=5+5)
Definition/test_goto_imported_file_at_lhs_index-2                       6.35µs ± 4%  6.44µs ± 0%    ~     (p=0.690 n=5+5)
Definition/test_goto_imported_file_at_rhs_index-2                       6.55µs ± 1%  6.42µs ± 0%  -1.97%  (p=0.008 n=5+5)
Definition/goto_import_index-2                                          5.96µs ± 1%  5.91µs ± 1%  -0.90%  (p=0.016 n=5+5)
Definition/goto_attribute_of_nested_import-2                            7.45µs ± 0%  7.36µs ± 1%  -1.10%  (p=0.008 n=5+5)
Definition/goto_dollar_attribute-2                                      6.37µs ± 2%  6.43µs ± 1%    ~     (p=1.000 n=5+5)
Definition/goto_dollar_sub_attribute-2                                  7.05µs ± 1%  7.00µs ± 1%    ~     (p=0.056 n=5+5)
Definition/goto_dollar_doesn't_follow_to_imports-2                      6.49µs ± 1%  6.40µs ± 0%  -1.32%  (p=0.008 n=5+5)
Definition/goto_attribute_of_nested_import_no_object_intermediary-2     6.63µs ± 1%  6.52µs ± 1%  -1.59%  (p=0.008 n=5+5)
Definition/goto_self_in_import_in_binary-2                              40.5µs ± 1%  38.8µs ± 2%  -4.11%  (p=0.008 n=5+5)
Definition/goto_self_attribute_from_local-2                             6.12µs ± 0%  6.03µs ± 0%  -1.42%  (p=0.008 n=5+5)
Definition/goto_function_parameter_from_inside_function-2               6.26µs ± 1%  6.20µs ± 1%  -1.05%  (p=0.008 n=5+5)
Definition/goto_local_func_param-2                                      6.60µs ± 0%  6.51µs ± 0%  -1.38%  (p=0.008 n=5+5)
Definition/goto_self_complex_scope_1-2                                  6.68µs ± 3%  6.73µs ± 1%    ~     (p=0.952 n=5+5)
Definition/goto_self_complex_scope_2-2                                  7.36µs ± 5%  7.38µs ± 0%    ~     (p=0.690 n=5+5)
Definition/goto_with_overrides:_clobber_string-2                        94.5µs ± 1%  92.8µs ± 3%    ~     (p=0.151 n=5+5)
Definition/goto_with_overrides:_clobber_nested_string-2                 97.1µs ± 3%  95.7µs ± 2%    ~     (p=0.421 n=5+5)
Definition/goto_with_overrides:_clobber_map-2                           93.3µs ± 1%  96.4µs ±14%    ~     (p=0.841 n=5+5)
Definition/goto_with_overrides:_map_(multiple_definitions)-2            99.5µs ± 8%  93.5µs ± 1%  -5.99%  (p=0.008 n=5+5)
Definition/goto_with_overrides:_nested_map_(multiple_definitions)-2      107µs ± 2%   101µs ± 0%  -4.92%  (p=0.008 n=5+5)
Definition/goto_with_overrides:_string_carried_from_super-2             94.3µs ± 2%  91.9µs ± 1%  -2.52%  (p=0.008 n=5+5)
Definition/goto_with_overrides:_nested_string_carried_from_super-2      96.5µs ± 0%  94.1µs ± 1%  -2.52%  (p=0.008 n=5+5)
Definition/goto_with_overrides:_string_carried_from_local-2             97.3µs ± 3%  94.7µs ± 0%  -2.64%  (p=0.008 n=5+5)
Definition/goto_with_overrides:_string_carried_from_import-2            96.6µs ± 1%  94.8µs ± 1%  -1.90%  (p=0.008 n=5+5)
Definition/goto_with_overrides:_string_carried_from_second_import-2     97.4µs ± 3%  94.5µs ± 1%  -2.94%  (p=0.008 n=5+5)
Definition/goto_deeply_nested_imported_attribute-2                      10.2µs ± 0%  10.0µs ± 1%  -1.36%  (p=0.008 n=5+5)
Definition/goto_deeply_nested_imported_attribute_through_self-2         47.4µs ± 2%  45.3µs ± 1%  -4.33%  (p=0.008 n=5+5)
Definition/goto_computed_field_name_object_field-2                      6.43µs ± 1%  6.30µs ± 0%  -1.89%  (p=0.008 n=5+5)
Definition/goto_field_through_function-2                                6.58µs ± 0%  6.43µs ± 0%  -2.35%  (p=0.016 n=4+5)
Definition/goto_field_through_function-created_object-2                 72.9µs ± 3%  70.4µs ± 1%  -3.37%  (p=0.008 n=5+5)