docs(i): Replace broken DQL link in README (#3274)

## Relevant issue(s)

Resolves #3269 

## Description

This is a change to update a broken link in the README.
This changes the target URI to point to an extant page in the docs.
FROM:

https://docs.source.network/references/query-specification/query-language-overview
TO:

https://docs.source.network/defradb/references/query-specification/query-language-overview

NO CODE CHANGES

## Tasks

- [NA] I made sure the code is well commented, particularly
hard-to-understand areas.
- [X] I made sure the repository-held documentation is changed
accordingly.
- [X] I made sure the pull request title adheres to the conventional
commit style (the subset used in the project can be found in
[tools/configs/chglog/config.yml](tools/configs/chglog/config.yml)).
- [NA] I made sure to discuss its limitations such as threats to
validity, vulnerability to mistake and misuse, robustness to
invalidation of assumptions, resource requirements, ...

## How has this been tested?

I manually followed the old link and the new link. Old was a broken
link. New is a proposed correct link.

Specify the platform(s) on which this was tested:
- MacOS

README.md

@@ -11,7 +11,7 @@
   </picture>
 </p>
 
-DefraDB is a user-centric database that prioritizes data ownership, personal privacy, and information security. Its data model, powered by the convergence of [MerkleCRDTs](https://arxiv.org/pdf/2004.00107.pdf) and the content-addressability of [IPLD](https://docs.ipld.io/), enables a multi-write-master architecture. It features [DQL](https://docs.source.network/references/query-specification/query-language-overview), a query language compatible with GraphQL but providing extra convenience. By leveraging peer-to-peer networking it can be deployed nimbly in novel topologies. Access control is determined by a relationship-based DSL, supporting document or field-level policies, secured by the SourceHub network. DefraDB is a core part of the [Source technologies](https://source.network/) that enable new paradigms of decentralized data and access-control management, user-centric apps, data trustworthiness, and much more.
+DefraDB is a user-centric database that prioritizes data ownership, personal privacy, and information security. Its data model, powered by the convergence of [MerkleCRDTs](https://arxiv.org/pdf/2004.00107.pdf) and the content-addressability of [IPLD](https://docs.ipld.io/), enables a multi-write-master architecture. It features [DQL](https://docs.source.network/defradb/references/query-specification/query-language-overview), a query language compatible with GraphQL but providing extra convenience. By leveraging peer-to-peer networking it can be deployed nimbly in novel topologies. Access control is determined by a relationship-based DSL, supporting document or field-level policies, secured by the SourceHub network. DefraDB is a core part of the [Source technologies](https://source.network/) that enable new paradigms of decentralized data and access-control management, user-centric apps, data trustworthiness, and much more.
 
 Read the documentation on [docs.source.network](https://docs.source.network/).