Bump requests from 2.11.1 to 2.20.0

Bumps [requests](https://github.com/psf/requests) from 2.11.1 to 2.20.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/master/HISTORY.md)
- [Commits](psf/requests@v2.11.1...v2.20.0)

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -18,7 +18,6 @@
 # In applying this license, CERN does not
 # waive the privileges and immunities granted to it by virtue of its status
 # as an Intergovernmental Organization or submit itself to any jurisdiction.
-
 alembic==0.8.10           # via flask-alembic
 amqp==2.2.1               # via invenio-queues, kombu
 angular-gettext-babel==0.3  # via invenio-search-ui
@@ -28,8 +27,9 @@ billiard==3.5.0.3         # via celery
 binaryornot==0.4.0        # via cookiecutter
 blinker==1.4              # via flask-mail, flask-principal, invenio-oauthclient, invenio-records
 celery==4.1
+certifi==2019.11.28       # via requests
 cffi==1.8.3               # via cryptography
-chardet==2.3.0            # via binaryornot, doschema
+chardet==3.0.4            # via binaryornot, doschema, requests
 click==6.6                # via cookiecutter, dojson, doschema, flask
 cookiecutter==1.4.0       # via invenio-base
 cryptography==1.5.2       # via invenio-accounts, invenio-oauthclient, sqlalchemy-utils
@@ -62,7 +62,7 @@ flask==0.11.1             # via flask-alembic, flask-assets, flask-babelex, flas
 fs==0.5.4                 # via invenio-files-rest
 future==0.16.0            # via cookiecutter, invenio-accounts
 httplib2==0.9.2
-idna==2.1                 # via cryptography
+idna==2.7                 # via cryptography, requests
 infinity==1.4             # via intervals
 intervals==0.8.0          # via wtforms-components
 invenio-access==1.0.0a11
@@ -84,7 +84,6 @@ invenio-marc21==1.0.0a5
 invenio-oaiserver==1.0.0a13
 invenio-oauth2server==1.0.0a14
 invenio-oauthclient==1.0.0b2
-invenio-pidrelations==v1.0.0a4
 invenio-pidstore==1.0.0b2
 invenio-query-parser==0.6.0
 invenio-queues==1.0.0a1   # via invenio-stats
@@ -129,7 +128,7 @@ python-geoip==1.2         # via invenio-stats
 pytz==2016.7              # via babel, celery, invenio-indexer
 redis==2.10.5             # via invenio-accounts, invenio-celery, invenio-queues
 requests-oauthlib==0.7.0  # via flask-oauthlib
-requests==2.11.1          # via datacite, easywebdav, invenio-search, requests-oauthlib
+requests==2.20.0          # via datacite, easywebdav, invenio-search, requests-oauthlib
 robot-detection==0.4      # via invenio-stats
 simplejson==3.10.0        # via dojson
 simplekv==0.10.0          # via flask-kvsession
@@ -140,7 +139,7 @@ sqlalchemy-utils[encrypted]==0.32.14  # via invenio-accounts, invenio-db, inveni
 sqlalchemy==1.1.11        # via alembic, flask-alembic, flask-sqlalchemy, invenio-db, sqlalchemy-continuum, sqlalchemy-utils, wtforms-alchemy
 ua-parser==0.7.3          # via invenio-accounts
 uritools==2.0.0           # via invenio-oauthclient
-urllib3==1.19             # via elasticsearch
+urllib3==1.24.3           # via elasticsearch, requests
 validators==0.11.0        # via wtforms-components
 vine==1.1.4               # via amqp
 webargs==1.4.0            # via invenio-files-rest, invenio-oaiserver, invenio-records-rest