requirements-docs.txt: add urllib3~=1.26.15

workaround for:
exception: urllib3 v2.0 only supports OpenSSL 1.1.1+, currently the
'ssl' module is compiled with 'OpenSSL 1.0.2k-fips  26 Jan 2017'

Issue-ID: INF-428

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Change-Id: Iaa54727b525cc0038f8cf46991c9431a237480ba
diff --git a/docs/requirements-docs.txt b/docs/requirements-docs.txt
index 5d3a810..1b72eea 100644
--- a/docs/requirements-docs.txt
+++ b/docs/requirements-docs.txt
@@ -4,3 +4,4 @@
 sphinxcontrib-httpdomain
 recommonmark
 lfdocs-conf
+urllib3~=1.26.15
diff --git a/docs/tox.ini b/docs/tox.ini
index dabc92c..256c184 100644
--- a/docs/tox.ini
+++ b/docs/tox.ini
@@ -14,11 +14,12 @@
     sphinxcontrib-httpdomain
     recommonmark
     lfdocs-conf
+    urllib3~=1.26.15
     
 commands =
     sphinx-build -W -b html -n -d {envtmpdir}/doctrees ./docs/ {toxinidir}/docs/_build/html
     echo "Generated docs available in {toxinidir}/docs/_build/html"
-whitelist_externals = echo
+allowlist_externals = echo
 
 [testenv:docs-linkcheck]
 basepython = python3
@@ -27,5 +28,6 @@
        sphinxcontrib-httpdomain
        recommonmark
        lfdocs-conf
+       urllib3~=1.26.15
 commands = sphinx-build -W -b linkcheck -d {envtmpdir}/doctrees ./docs/ {toxinidir}/docs/_build/linkcheck
 
diff --git a/tox.ini b/tox.ini
index db50ddf..f2888fc 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,9 +1,9 @@
+# documentation only
 [tox]
 minversion = 2.0
 envlist =
     docs,
     docs-linkcheck,
-
 skipsdist = true
 
 [testenv:docs]
@@ -14,13 +14,12 @@
     sphinxcontrib-httpdomain
     recommonmark
     lfdocs-conf
+    urllib3~=1.26.15
     
 commands =
     sphinx-build -W -b html -n -d {envtmpdir}/doctrees ./docs/ {toxinidir}/docs/_build/html
-
     echo "Generated docs available in {toxinidir}/docs/_build/html"
-
-whitelist_externals = echo
+allowlist_externals = echo
 
 [testenv:docs-linkcheck]
 basepython = python3
@@ -29,4 +28,5 @@
        sphinxcontrib-httpdomain
        recommonmark
        lfdocs-conf
+       urllib3~=1.26.15
 commands = sphinx-build -W -b linkcheck -d {envtmpdir}/doctrees ./docs/ {toxinidir}/docs/_build/linkcheck