Closes #7687: Update CentOS installation docs

docs/installation/1-postgresql.md

@@ -21,9 +21,6 @@ This section entails the installation and configuration of a local PostgreSQL da
     sudo postgresql-setup --initdb
     ```
 
-    !!! info
-        PostgreSQL 9.6 and later are available natively on CentOS 8.2. If using an earlier CentOS release, you may need to [install it from an RPM](https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/).
-
     CentOS configures ident host-based authentication for PostgreSQL by default. Because NetBox will need to authenticate using a username and password, modify `/var/lib/pgsql/data/pg_hba.conf` to support MD5 authentication by changing `ident` to `md5` for the lines below:
 
     ```no-highlight

docs/installation/3-netbox.md

@@ -17,8 +17,13 @@ Begin by installing all system packages required by NetBox and its dependencies.
 
 === "CentOS"
 
+    !!! warning
+        CentOS 8 does not provide Python 3.7 or later via its native package manager. You will need to install it via some other means. [Here is an example](https://tecadmin.net/install-python-3-7-on-centos-8/) of installing Python 3.7 from source.
+
+    Once you have Python 3.7 or later installed, install the remaining system packages:
+
     ```no-highlight
-    sudo yum install -y gcc python36 python36-devel python3-pip libxml2-devel libxslt-devel libffi-devel libpq-devel openssl-devel redhat-rpm-config
+    sudo yum install -y gcc libxml2-devel libxslt-devel libffi-devel libpq-devel openssl-devel redhat-rpm-config
     ```
 
 Before continuing with either platform, update pip (Python's package management tool) to its latest release:

docs/installation/index.md

@@ -1,6 +1,6 @@
 # Installation
 
-The installation instructions provided here have been tested to work on Ubuntu 20.04 and CentOS 8.2. The particular commands needed to install dependencies on other distributions may vary significantly. Unfortunately, this is outside the control of the NetBox maintainers. Please consult your distribution's documentation for assistance with any errors.
+The installation instructions provided here have been tested to work on Ubuntu 20.04 and CentOS 8.3. The particular commands needed to install dependencies on other distributions may vary significantly. Unfortunately, this is outside the control of the NetBox maintainers. Please consult your distribution's documentation for assistance with any errors.
 
 The following sections detail how to set up a new instance of NetBox: