Update cheatsheets

tldr/kubectl-exec

@@ -0,0 +1,13 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# kubectl exec
+
+> Execute a command in a container.
+> More information: <https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#exec>.
+
+- Open Bash in a pod, using the first container by default:
+
+`kubectl exec {{pod_name}} {{-it|--stdin --tty]}} -- bash`