Add SPDX 3.0 page

Also make SPDX 2.3 and SPDX 3.0 page name consistent to each other

Signed-off-by: Arthit Suriyawongkul <arthit@gmail.com>

Author: bact

content/crosswalk/spdx2_3.md content/crosswalk/spdx-2-3.mdcontent/crosswalk/spdx2_3.md renamed to content/crosswalk/spdx-2-3.md

@@ -0,0 +1,20 @@
+---
+title: "Crosswalk for SPDX 3.0 Document"
+image: "/img/spdx.png"
+date: "2025-09-30"
+---
+
+The [System Package Data Exchange® (SPDX®)](https://spdx.dev/),
+formerly known as the *Software Package Data Exchange*, specification
+defines a standard data format for communicating the component and metadata
+information associated with software packages and beyond, widely known as
+"software bill of materials" or "SBOM".
+An SPDX document can be associated with a set of software packages, files or snippets.
+SPDX 3.0 can describe datasets and be used in non-SBOM contexts.
+
+SPDX 3.0 supports JSON-LD serialization format and often uses `.spdx.json`,
+`.spdx.jsonld`, `.spdx3.json`, or `.spdx3.jsonld` as the file extension.
+
+The crosswalk for the SPDX 3.0 document as follows:
+
+{{< crosswalk name="SPDX 3.0" >}}