docs: update README to include LoRA-GGPO details for FLUX.1 training

Author: kohya-ss

README.md

@@ -15,6 +15,8 @@ The command to install PyTorch is as follows:
 ### Recent Updates
 
 Mar 30, 2025:
+- LoRA-GGPO is added for FLUX.1 LoRA training. Thank you to rockerBOO for PR [#1974](https://github.com/kohya-ss/sd-scripts/pull/1974). 
+  - Specify `--network_args ggpo_sigma=0.03 ggpo_beta=0.01` in the command line or `network_args = ["ggpo_sigma=0.03", "ggpo_beta=0.01"]` in .toml file. See PR for details.
 - The interpolation method for resizing the original image to the training size can now be specified. Thank you to rockerBOO for PR [#1939](https://github.com/kohya-ss/sd-scripts/pull/1939).
 
 Mar 20, 2025: