Pipenv automatically upgrade dependencies

Pipfile

[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true

[dev-packages]

[packages]
click = "*"
requests = "*"

[requires]
python_version = "3.7"

Pipfile.lock

{
    "_meta": {
        "hash": {
            "sha256": "85d29b2cfc5d4e61d41de6948621b329e2e1c6d692edeabc70fd0d8413e298db"
        },
        "pipfile-spec": 6,
        "requires": {
            "python_version": "3.7"
        },
        "sources": [
            {
                "name": "pypi",
                "url": "https://pypi.org/simple",
                "verify_ssl": true
            }
        ]
    },
    "default": {
        "certifi": {
            "hashes": [
                "sha256:59b7658e26ca9c7339e00f8f4636cdfe59d34fa37b9b04f6f9e9926b3cece1a5",
                "sha256:b26104d6835d1f5e49452a26eb2ff87fe7090b89dfcaee5ea2212697e1e1d7ae"
            ],
            "version": "==2019.3.9"
        },
        "chardet": {
            "hashes": [
                "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
                "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
            ],
            "version": "==3.0.4"
        },
        "click": {
            "hashes": [
                "sha256:29f99fc6125fbc931b758dc053b3114e55c77a6e4c6c3a2674a2dc986016381d",
                "sha256:f15516df478d5a56180fbf80e68f206010e6d160fc39fa508b65e035fd75130b"
            ],
            "index": "pypi",
            "version": "==6.7"
        },
        "idna": {
            "hashes": [
                "sha256:c357b3f628cf53ae2c4c05627ecc484553142ca23264e593d327bcde5e9c3407",
                "sha256:ea8b7f6188e6fa117537c3df7da9fc686d485087abf6ac197f9c46432f7e4a3c"
            ],
            "version": "==2.8"
        },
        "requests": {
            "hashes": [
                "sha256:502a824f31acdacb3a35b6690b5fbf0bc41d63a24a45c4004352b0242707598e",
                "sha256:7bf2a778576d825600030a110f3c0e3e8edc51dfaafe1c146e39a2027784957b"
            ],
            "index": "pypi",
            "version": "==2.21.0"
        },
        "urllib3": {
            "hashes": [
                "sha256:b246607a25ac80bedac05c6f282e3cdaf3afb65420fd024ac94435cabe6e18d1",
                "sha256:dbe59173209418ae49d485b87d1681aefa36252ee85884c31346debd19463232"
            ],
            "version": "==1.25.3"
        }
    },
    "develop": {}
}

test.sh

# currently request==2.21.0 and click==6.7
# upgrade requests to latest version
pipenv update --selective-upgrade requests
# now requests==2.22.0 AND click==7.0 and there is no relation between click and requests
 
pipenv graph
# Click==7.0
# requests==2.22.0
#   - certifi [required: >=2017.4.17, installed: 2019.3.9]
#   - chardet [required: >=3.0.2,<3.1.0, installed: 3.0.4]
#   - idna [required: >=2.5,<2.9, installed: 2.8]
#   - urllib3 [required: >=1.21.1,<1.26,!=1.25.1,!=1.25.0, installed: 1.25.3]