Make backend.StateMgr accept a context (#780)

Signed-off-by: Marcin Wyszynski <marcin.pixie@gmail.com>

internal/command/state_push.go

@@ -4,6 +4,7 @@
 package command
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"os"
@@ -97,8 +98,10 @@ func (c *StatePushCommand) Run(args []string) int {
 		return 1
 	}
 
+	ctx := context.TODO()
+
 	// Get the state manager for the currently-selected workspace
-	stateMgr, err := b.StateMgr(workspace)
+	stateMgr, err := b.StateMgr(ctx, workspace)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load destination state: %s", err))
 		return 1