fix: use Jenkins python3.8 agent

Jenkinsfile

@@ -4,9 +4,7 @@
 
 pipeline {
     agent {
-        dockerfile {
-            filename 'Dockerfile.CI'
-        }
+        label 'python3.8'
     }
 
     environment {

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 min_version = 4.3.3
-envlist = 
+envlist =
     py3{8, 9, 10}
     flake8
     black
@@ -23,6 +23,11 @@ python = python3.11
 skip_install = true
 package = deepaas
 
+[jenkins]
+python = python3.8
+skip_install = true
+package = deepaas
+
 [pytest]
 addopts = -p no:warnings
 
@@ -68,10 +73,10 @@ basepython = python3.12
 
 [flake8]
 # Black default line length is 88
-max-line-length = 88 
+max-line-length = 88
 show-source = True
 builtins = _
-exclude = 
+exclude =
     .venv
     .git
     .tox
@@ -82,8 +87,8 @@ exclude =
     build
 
 [testenv:flake8]
-basepython = {[base]python}
-skip_install = {[base]skip_install}
+basepython = {[jenkins]python}
+skip_install = {[jenkins]skip_install}
 deps =
     flake8>=4.0,<4.1
     flake8-bugbear>=22.3,<22.4
@@ -112,7 +117,7 @@ commands = bandit -r {[base]package} -x tests -s B110,B410
 basepython = {[base]python}
 deps = {[testenv:bandit]deps}
 skip_install = {[base]skip_install}
-commands = 
+commands =
     - mkdir /tmp/bandit
     - bandit -r {[base]package} -x tests -s B110,B410 -f html -o /tmp/bandit/index.html
 
@@ -128,21 +133,21 @@ commands = oslo-config-generator --config-file=etc/{[base]package}-config-genera
 
 [testenv:docs]
 basepython = {[base]python}
-deps = 
+deps =
     -r {toxinidir}/doc/requirements.txt
 commands =
     rm -rf doc/build
     python setup.py build_sphinx
 
-[testenv:mypy]                                                                  
-description = Static type checks                              
+[testenv:mypy]
+description = Static type checks
 basepython = {[base]python}
-deps = 
+deps =
     mypy
-commands =                                                                      
+commands =
     mypy --config-file mypy.ini -p {[base]package}
 
 [testenv:pip-missing-reqs]
-basepython = {[base]python}
+basepython = {[jenkins]python}
 deps = pip_check_reqs
-commands=pip-missing-reqs -d --ignore-file={[base]package}/tests/* {[base]package}
+commands=pip-missing-reqs -d --ignore-file={[jenkins]package}/tests/* {[jenkins]package}