Fix obs4MIPs frequency in recipe_bock20jgr_fig_1-4.yml

[bouweandela]

Description

The frequency was set to mo for obs4MIPs dataset GPCP-V2.3, therefore ESMValCore cannot find the data on ESGF. This corrects the issue.

---

Before you get started

• [x] ☝ Create an issue to discuss what you are going to do

Checklist

It is the responsibility of the author to make sure the pull request is ready to review. The icons indicate whether the item will be subject to the 🛠 Technical or 🧪 Scientific review.

• [x] 🛠 This pull request has a descriptive title
• [x] 🛠 Code is written according to the code quality guidelines
• [x] 🛠 Documentation is available
• [x] 🛠 Tests run successfully
• [x] 🛠 The list of authors is up to date
• [x] 🛠 All checks below this pull request were successful

New or updated recipe/diagnostic

• [x] 🧪 Recipe runs successfully

---

To help with the number of pull requests:

• 🙏 We kindly ask you to review two other open pull requests in this repository