fix: add DOIs for PDFs of previous versions

Author: musicEnfanthen

resources/schemas.md

@@ -36,7 +36,7 @@ A detailed overview of the changes for the MEI 5.1 schema is available here: [ht
 # Previous Versions of MEI
 
 - [MEI v5.0 (2023)](https://github.com/music-encoding/music-encoding/releases/tag/v5.0)
-  - MEI 5.0 Guidelines ([PDF](https://zenodo.org/records/10040258)); DOI: [10.5281/zenodo.10040258]( https://doi.org/10.5281/zenodo.10040258)
+  - MEI 5.0 Guidelines ([PDF](https://zenodo.org/records/10040258); DOI: [10.5281/zenodo.10040258](https://doi.org/10.5281/zenodo.10040258))
   - RelaxNG schemata:
     - [MEI All](https://music-encoding.org/schema/5.0/mei-all.rng)
     - [MEI All Anystart](https://music-encoding.org/schema/5.0/mei-all_anyStart.rng)
@@ -53,15 +53,15 @@ A detailed overview of the changes for the MEI 5.1 schema is available here: [ht
     - [MEI Mensural](https://music-encoding.org/schema/4.0.1/mei-Mensural.rng)
     - [MEI Neumes](https://music-encoding.org/schema/4.0.1/mei-Neumes.rng)
 - [MEI v3.0.0 (2016)](https://github.com/music-encoding/music-encoding/releases/tag/v3.0.0)
-  - MEI 3.0.0 Guidelines ([PDF](https://github.com/music-encoding/music-encoding/releases/download/v3.0.0/MEI_Guidelines_v3.0.0.pdf))
+  - MEI 3.0.0 Guidelines ([PDF](https://zenodo.org/records/10040230); DOI: [10.5281/zenodo.10040230](https://doi.org/10.5281/zenodo.10040230))
   - RelaxNG schemata:
     - [MEI All](https://music-encoding.org/schema/3.0.0/mei-all.rng)
     - [MEI All Anystart](https://music-encoding.org/schema/3.0.0/mei-all_anyStart.rng)
     - [MEI CMN](https://music-encoding.org/schema/3.0.0/mei-CMN.rng)
     - [MEI Mensural](https://music-encoding.org/schema/3.0.0/mei-Mensural.rng)
     - [MEI Neumes](https://music-encoding.org/schema/3.0.0/mei-Neumes.rng)
 - [MEI 2013 (v2.1.1)](https://github.com/music-encoding/music-encoding/releases/tag/MEI2013_v2.1.1)
-  - MEI 2013 Guidelines ([PDF](https://github.com/music-encoding/music-encoding/releases/download/MEI2013_v2.1.1/MEI_Guidelines_2013_v2.1.1.pdf))
+  - MEI 2013 Guidelines ([PDF](https://zenodo.org/records/10040218); DOI: [10.5281/zenodo.10040218](https://doi.org/10.5281/zenodo.10040218))
   - RelaxNG schemata:
     - [MEI All](https://music-encoding.org/schema/2.1.1/mei-all.rng)
     - [MEI All Anystart](https://music-encoding.org/schema/2.1.1/mei-all_anyStart.rng)
@@ -70,9 +70,9 @@ A detailed overview of the changes for the MEI 5.1 schema is available here: [ht
     - [MEI Neumes](https://music-encoding.org/schema/2.1.1/mei-Neumes.rng)
 - [MEI 2012](https://github.com/music-encoding/music-encoding/releases/tag/MEI2012_v2.0.0)
   - MEI 2012 Release ([ZIP](https://github.com/music-encoding/music-encoding/archive/MEI2012_v2.0.0.zip))
-  - MEI 2012 Guidelines ([PDF](https://music-encoding.org/downloads/MEI_Guidelines_2012_v2.0.0.pdf))
+  - MEI 2012 Guidelines ([PDF](https://zenodo.org/records/10040170); DOI: [10.5281/zenodo.10040170](https://doi.org/10.5281/zenodo.10040170))
 - [MEI 2011-05](https://github.com/music-encoding/music-encoding/releases/tag/MEI_release_2011-05)
   - MEI 2011-05 Release ([ZIP](https://github.com/music-encoding/music-encoding/archive/MEI_release_2011-05.zip))
 - [MEI 2010-05](https://github.com/music-encoding/music-encoding/releases/tag/MEI_release_2010-05)
   - MEI 2010-05 Release ([ZIP](https://github.com/music-encoding/music-encoding/archive/MEI_release_2010-05.zip))
-  - Tag Library ([PDF](https://music-encoding.org/downloads/MEI_TagLibrary_2010-05.pdf))
+  - Tag Library ([PDF](https://zenodo.org/records/10040125); DOI: [10.5281/zenodo.10040125](https://doi.org/10.5281/zenodo.10040125))