Rename nightly_6_1 params to nightly_next (#144)

Rename nightly_6_1 params to nightly_next; see
apple/swift-nio#3122

Author: rnro

.github/workflows/main.yml

@@ -14,7 +14,7 @@ jobs:
       linux_5_9_arguments_override: "--explicit-target-dependency-import-check error"
       linux_5_10_arguments_override: "--explicit-target-dependency-import-check error"
       linux_6_0_arguments_override: "--explicit-target-dependency-import-check error"
-      linux_nightly_6_1_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error"
       linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
 
   integration-test:

.github/workflows/pull_request.yml

@@ -18,7 +18,7 @@ jobs:
       linux_5_9_arguments_override: "--explicit-target-dependency-import-check error"
       linux_5_10_arguments_override: "--explicit-target-dependency-import-check error"
       linux_6_0_arguments_override: "--explicit-target-dependency-import-check error"
-      linux_nightly_6_1_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error"
       linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
 
   integration-test: