Update outbound IPs for all GCP regions

[AnouckColson]

Where on docs.platform.sh should be changed?

https://docs.platform.sh/development/regions.html#public-ip-addresses

https://docs.upsun.com/development/regions.html#public-ip-addresses

The rollout of the new IPs is going to be progressive, so we need to document them while still keeping the existing ones for a while, making the situation clear for users.

Recommendation to avoid making things overcrowded/complicated with the existing table:

1. Create a section about the outbound IP change (to explain why users need to allow both old & new IPs for a while, and that they will be informed when they can remove the old ones).
2. Update the content of the Outbound IPs cell in the table to only include a link to that section, instead of adding more IPs to a table whose readability is already mediocre.
3. Once we get confirmation that the old IPs have become obsolete and users should deprecate them, remove the dedicated section in a future PR, and update the Outbound IPs cell to feature only the new IPs.

What exactly should be updated?

Within 3 to 6 months, the following outbound IPs will be implemented and need to be documented:

uk-1.platform.sh

• 35.246.36.142
• 34.147.217.161
• 34.89.33.176

de-2.platform.sh

• 34.159.207.210
• 34.159.181.149
• 34.107.79.7

ch-1.platform.sh

• 34.65.197.163
• 34.65.144.16
• 34.65.72.28

us-4.platform.sh

• 104.196.203.234
• 34.148.171.57
• 35.243.131.172

Additional context

No response