Update Swift version requirements in README

.devcontainer/Dockerfile

@@ -1,3 +1,4 @@
+# **Do not change without a global search/replace for this version string.**
 ARG SWIFT_VERSION=5.10
 # Other ARG declarations must follow FROM
 FROM swift:${SWIFT_VERSION}

.devcontainer/devcontainer.json

@@ -3,6 +3,7 @@
     "build": {
         "dockerfile": "Dockerfile",
         "args": {
+            // **Do not change without a global search/replace for this version string.**
             "SWIFT_VERSION" : "5.10",
             "HYLO_LLVM_BUILD_TYPE": "${localEnv:HYLO_LLVM_BUILD_TYPE:MinSizeRel}"
         }

.github/workflows/build-and-test.yml

@@ -44,6 +44,7 @@ on:
 env:
   spm-build-options: -Xswiftc -enable-testing --explicit-target-dependency-import-check error
   spm-test-options: --parallel
+  # **Do not change without a global search/replace for this version string.**
   swift-version: '5.10'
 
 jobs:

.github/workflows/doc-extraction.yml

@@ -30,6 +30,7 @@ jobs:
     env:
       llvm_url_prefix: https://github.com/hylo-lang/llvm-build/releases/download/20240303-215025
       llvm_package_basename: llvm-17.0.6-arm64-apple-darwin23.3.0-MinSizeRel
+      # **Do not change without a global search/replace for this version string.**
       swift-version: '5.10'
 
     steps:

.spi.yml

@@ -2,6 +2,7 @@ version: 1
 builder:
   configs:
   - platform: linux
+    # **Do not change without a global search/replace for this version string.**
     swift_version: '5.10'
     image: registry.gitlab.com/finestructure/spi-images:hylo-5.10-latest
     documentation_targets:
@@ -21,12 +22,3 @@ builder:
     --source-service-base-url, https://github.com/hylo-lang/hylo/blob/main,
     --checkout-path, .
     ]
-  - platform: linux
-    swift_version: '5.9'
-    image: registry.gitlab.com/finestructure/spi-images:hylo-5.9-latest
-  - platform: linux
-    swift_version: '5.8'
-    image: registry.gitlab.com/finestructure/spi-images:hylo-5.8-latest
-  - platform: linux
-    swift_version: '5.7'
-    image: registry.gitlab.com/finestructure/spi-images:hylo-5.7-latest

Package.swift

@@ -1,3 +1,4 @@
+// **Do not change without a global search/replace for this version string.**
 // swift-tools-version:5.10
 import Foundation
 import PackageDescription

README.md

@@ -11,7 +11,7 @@ Please visit our [website](https://hylo-lang.org) to get more information about
 ## Developement/Use Requirements
 
 This project is written in [Swift](https://swift.org) and distributed in the form of a package, built with [Swift Package Manager](https://swift.org/package-manager/).
-You will need Swift 5.9 or higher to build the compiler from sources.
+You will need Swift 5.10 or higher to build the compiler from sources.
 
 **This repository contains
 [submodules](https://git-scm.com/book/en/v2/Git-Tools-Submodules)**,