Fix how to add julia releases with juliaup

julia-intro/docs/julia-intro-installation.ipynb

@@ -138,15 +138,21 @@
     "\n",
     "to show all the versions of Julia available.\n",
     "\n",
-    "We will work with the newest version on all platforms, 1.9.3 so simply type\n",
+    "We will work with the newest version on all platforms, 1.10.4 so simply type\n",
     "\n",
     "```bash\n",
-    "juliaup install 1.9.3\n",
+    "juliaup add 1.10.4\n",
     "```\n",
     "\n",
     "to set that up.\n",
     "\n",
-    "The big bonus with `juliaup` is that you can easily have multiple Julia releases installed at once, and Juliaup will let you configure which is your default at any point in time.\n"
+    "The big bonus with `juliaup` is that you can easily have multiple Julia releases installed at once, and Juliaup will let you configure which is your default at any point in time.\n",
+    "\n",
+    "Keep juliaup updated with\n",
+    "\n",
+    "```bash\n",
+    "juliaup self update\n",
+    "```\n"
    ]
   },
   {