feat: gate set-env/add-path and render annotation locations (#1109)

`::set-env::` and `::add-path::` let a step rewrite the environment of every later step from its own output, which the runner honoured silently. They are now refused, as GitHub has done since 2020, and `ACTIONS_ALLOW_UNSECURE_COMMANDS` opts back in per step or job. Support for that variable is new here too, and is the only opt-in, matching GitHub rather than adding a runner config key on top.

Annotations keep their source location: Gitea has no annotation store and its web UI strips command properties, so `::error file=main.go,line=12::msg` is rendered as `::error::main.go:12: msg`.

`DEVELOPMENT.md` writes down the log line encoding rules this relies on.

---------

Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1109
Reviewed-by: silverwind <[email protected]>
Co-authored-by: bircni <[email protected]>

act/runner/action_composite.go

@@ -186,10 +186,10 @@ func (rc *RunContext) compositeExecutor(action *model.Action) *compositeSteps {
 			err := rc.newCompositeCommandExecutor(step.main())(ctx)
 
 			if err != nil {
-				logger.Errorf("%v", err)
+				logger.Errorf("##[error]%s", EscapeCommandData(err.Error()))
 				common.SetJobError(ctx, err)
 			} else if ctx.Err() != nil {
-				logger.Errorf("%v", ctx.Err())
+				logger.Errorf("##[error]%s", EscapeCommandData(ctx.Err().Error()))
 				common.SetJobError(ctx, ctx.Err())
 			}
 			return nil
@@ -248,10 +248,10 @@ func newCompositeStepLogExecutor(runStep common.Executor, stepID string) common.
 		logger := common.Logger(ctx)
 		err := runStep(ctx)
 		if err != nil {
-			logger.Errorf("%v", err)
+			logger.Errorf("##[error]%s", EscapeCommandData(err.Error()))
 			common.SetJobError(ctx, err)
 		} else if ctx.Err() != nil {
-			logger.Errorf("%v", ctx.Err())
+			logger.Errorf("##[error]%s", EscapeCommandData(ctx.Err().Error()))
 			common.SetJobError(ctx, ctx.Err())
 		}
 		return nil