FIX - Deploying GPU instance

Small additions to one code block based on feedback from the US PCI team.

Author: SR-OVH-US

pages/public_cloud/compute/deploy_a_gpu_instance/guide.en-gb.md

@@ -57,6 +57,8 @@ sudo dpkg -i cuda-repo-XXXX-XXXXXX
 sudo apt-get update
 sudo apt-get upgrade
 sudo apt-get install cuda
+sudo apt-get install -y cuda-drivers
+sudo apt-get install linux-headers-$(uname -r)
 sudo reboot
 ```
 
@@ -157,4 +159,4 @@ Afterwards, all that’s left to do is to install the required driver, which wil
 
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-Join our [community of users](/links/community).
+Join our [community of users](/links/community).