installation updates (#136)

Author: badmonster0

README.md

@@ -33,7 +33,7 @@ If you're new to CocoIndex 🤗, we recommend checking out the 📖 [Documentati
 1. Install CocoIndex Python library
 
 ```bash
-pip install cocoindex
+pip install -U cocoindex
 ```
 
 2. Setup Postgres with pgvector extension; or bring up a Postgres database using docker compose:

docs/docs/getting_started/installation.md

@@ -12,7 +12,7 @@ To follow the steps in this guide, you'll need:
 
 ## 🌴 Install CocoIndex
 ```bash
-pip install cocoindex
+pip install -U cocoindex
 ```
 
 ## 📦 Install Postgres

docs/docs/getting_started/quickstart.md

@@ -21,7 +21,7 @@ We'll need to install a bunch of dependencies for this project.
 1.  Install CocoIndex:
 
     ```bash
-    pip install cocoindex
+    pip install -U cocoindex
     ```
 
 2.  You can skip this step if you already have a Postgres database with pgvector extension installed.