PYTHON-3898 Add coverage to all variants (mongodb#2705)

Author: blink1073

.codecov.yml

@@ -0,0 +1,4 @@
+# do not notify until at least 100 builds have been uploaded from the CI pipeline
+# you can also set after_n_builds on comments independently
+comment:
+  after_n_builds: 100

.evergreen/generated_configs/functions.yml

@@ -250,6 +250,7 @@ functions:
         working_dir: src
         include_expansions_in_env:
           - TOOLCHAIN_VERSION
+          - COVERAGE
       type: test
 
   # Upload coverage codecov
@@ -268,7 +269,7 @@ functions:
           - github_pr_number
           - github_pr_head_branch
           - github_author
-          - is_patch
+          - requester
           - branch_name
       type: test