Update cheatsheets

uptime

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+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# uptime
+
+> Tell how long the system has been running and other information.
+> More information: <https://www.gnu.org/software/coreutils/uptime>.
+
+- Print current time, uptime, number of logged-in users and other information:
+
+`uptime`
+
+- Show only the amount of time the system has been booted for:
+
+`uptime --pretty`
+
+- Print the date and time the system booted up at:
+
+`uptime --since`
+
+- Display version:
+
+`uptime --version`