Update LicenseDB index.json

update license index from latest LicenseDB.
LicenseDB commit: https://github.com/nexB/scancode-licensedb/tree/e12a124aa3b1aa83c99f2946973880c434ba5706
ScanCode Toolkit commit: https://github.com/nexB/scancode-toolkit/tree/887d56c3b471954c50af3a837f8e7a77c9f162a6

Signed-off-by: Ayan Sinha Mahapatra <[email protected]>

Author: AyanSinhaMahapatra

src/license_expression/data/license_key_index.json.ABOUT

@@ -1,6 +1,6 @@
 about_resource: scancode-licensedb-index.json
-download_url: https://github.com/nexB/scancode-licensedb/raw/b32930065192f3927eb957e22fdeee40cce4b197/docs/index.json
-spdx_license_list_version: 3.19
+download_url: https://github.com/nexB/scancode-licensedb/raw/eb22bc0f02585cec38865e323eaf079cc52ebcfb/docs/index.json
+spdx_license_list_version: 3.20
 name: scancode-licensedb-index.json
 license_expression: cc-by-4.0
 copyright: Copyright (c) nexB Inc. and others.