Drop compat with 8.18 (#223)

Author: Lysxia

.github/workflows/docker-action.yml

@@ -21,7 +21,6 @@ jobs:
           - 'rocq/rocq-prover:9.0'
           - 'coqorg/coq:8.20'
           - 'coqorg/coq:8.19'
-          - 'coqorg/coq:8.18'
       fail-fast: false
     steps:
       - uses: actions/checkout@v4

README.md

@@ -88,7 +88,7 @@ CoRN includes the following parts:
   - Vincent Semeria ([**@vincentse**](https://github.com/vincentse))
   - Xia Li-yao ([**@Lysxia**](https://github.com/Lysxia))
 - License: [GNU General Public License v2](LICENSE)
-- Compatible Coq versions: Coq 8.18 or greater
+- Compatible Coq versions: Coq 8.19 or greater
 - Additional dependencies:
   - [Math-Classes](https://github.com/coq-community/math-classes) 8.8.1 or
 greater, which is a library of abstract interfaces for mathematical

coq-corn.opam

@@ -46,7 +46,7 @@ build: [
 ]
 install: [make "install"]
 depends: [
-  "coq" {(>= "8.18" & < "9.1~") | (= "dev")}
+  "coq" {(>= "8.19" & < "9.1~") | (= "dev")}
   "coq-math-classes" {(>= "8.8.1") | (= "dev")}
   "coq-elpi" {(>= "1.18.0") | (= "dev")}
   "coq-bignums" 

meta.yml

@@ -81,13 +81,12 @@ license:
   identifier: GPL-2.0
 
 supported_coq_versions:
-  text: Coq 8.18 or greater
-  opam: '{(>= "8.18" & < "8.20~") | (= "dev")}'
+  text: Coq 8.19 or greater
+  opam: '{(>= "8.19" & < "8.20~") | (= "dev")}'
 
 tested_coq_opam_versions:
 - version: dev
 - version: "8.19"
-- version: "8.18"
 
 dependencies:
 - opam: