docs: Deprecate use of git.io URL shortener (#1851)

* Replace all instances of git.io shortened URLs with full URLs as git.io is
being killed off by GitHub on 2022-04-29.
   - c.f. https://github.blog/changelog/2022-04-25-git-io-deprecation/

README.rst

@@ -70,7 +70,8 @@ Alternatively the statistical model and observational data can be read from its
    >>> import pyhf
    >>> import requests
    >>> pyhf.set_backend("numpy")
-   >>> wspace = pyhf.Workspace(requests.get("https://git.io/JJYDE").json())
+   >>> url = "https://raw.githubusercontent.com/scikit-hep/pyhf/master/docs/examples/json/2-bin_1-channel.json"
+   >>> wspace = pyhf.Workspace(requests.get(url).json())
    >>> model = wspace.model()
    >>> data = wspace.data(model)
    >>> test_mu = 1.0

src/pyhf/cli/infer.py

@@ -63,7 +63,7 @@ def fit(
 
     .. code-block:: shell
 
-        $ curl -sL https://git.io/JJYDE | pyhf fit --value
+        $ curl -sL https://raw.githubusercontent.com/scikit-hep/pyhf/master/docs/examples/json/2-bin_1-channel.json | pyhf fit --value
 
         \b
         {
@@ -176,7 +176,7 @@ def cls(
 
     .. code-block:: shell
 
-        $ curl -sL https://git.io/JJYDE | pyhf cls
+        $ curl -sL https://raw.githubusercontent.com/scikit-hep/pyhf/master/docs/examples/json/2-bin_1-channel.json | pyhf cls
 
         \b
         {