Update vulnerability reporting instructions to include email contact and recommend IDEA version

Author: xterao

CONTRIBUTING.md

@@ -27,6 +27,8 @@ If you have any questions or suggestions, feel free to open an issue or contact
 
 ## Prerequisites
 
+- Install **IntelliJ IDEA** (2024.3 or later)
+  - We recommend using the latest stable version of IntelliJ IDEA.
 - Install **Git** and configure your GitHub access
 - Install **JDK 17**
 
@@ -125,7 +127,7 @@ For example, a bug fix branch might be named `fix/typo-in-readme`, and a new fea
 
 ## Submitting a Pull Request
 
-1. Fork the repository and create your branch from `main`.
+1. Create your branch from `main`.
 2. Make your changes and ensure all tests pass:
    ```sh
    ./gradlew check

SECURITY.md

@@ -4,24 +4,10 @@ We take all security bugs very seriously.
 ## Supported Versions
 
 The community fixes security bugs in the latest version.
-Depending on the severity of the issue and the age of the release, we may fix vulnerabilities in older versions, but we generally commit fixes only to the latest released version.
-
-Example:
-
-| Current Release | Supported for Security Fixes | Not Supported |
-|:---------------:|:----------------------------:|:-------------:|
-| 2.1             | 2.1                          |   2.x, 1.x    |
-| 3.0             | 3.0                          |   2.x, 1.x    |
-
-*If multiple major versions are maintained in the future, fixes may be applied to each major version.*
-
-Example:
-
-| Current Release | Supported for Security Fixes |    Not Supported     |
-|:---------------:|:----------------------------:|:--------------------:|
-| 2.1             |       2.1 ,latest 1.x        | older 2.x, older 1.x |
-| 3.0             | 3.0 ,latest 2.x, latest 1.x  | older 2.x,older 1.x  |
+We generally commit fixes only to the latest released version.
 
 ## Reporting Vulnerabilities
 
-To report a vulnerability, please register an [issue on GitHub](https://github.com/domaframework/doma-tools-for-intellij/issues).
+Email to the below address:
+
+- toshihiro.nakamura at gmail.com