readme: remove obsolete command description

Fixup: adeb pull command was changed in 925a9f5 but the readme file still had the description for the old version of the command.
diff --git a/README.md b/README.md
index a324111..a1aafc2 100644
--- a/README.md
+++ b/README.md
@@ -84,12 +84,7 @@
 If you have multiple devices connected, please add `-s <serialnumber>`.
 Serial numbers of all devices connected can be obtained by `adb devices`.
 
-* To update the adeb you cloned on your host, run:
-```
-adeb pull
-```
-
-To update an existing adeb clone on your host, run:
+* To update an existing adeb clone on your host, run:
 ```
 adeb git-pull
 ```