fix(sp1-build, workflows): docker tag (#1636)

.github/workflows/docker-publish-gnark.yml

@@ -3,6 +3,8 @@ name: docker-gnark
 
 on:
   push:
+    branches:
+      - "main"
     tags:
       - "v*.*.*"
   schedule:

.github/workflows/docker-publish.yml

@@ -3,6 +3,8 @@ name: docker
 
 on:
   push:
+    branches:
+      - "main"
     tags:
       - "v*.*.*"
   schedule:

crates/build/src/lib.rs

@@ -7,7 +7,7 @@ pub use build::execute_build_program;
 use clap::Parser;
 
 const BUILD_TARGET: &str = "riscv32im-succinct-zkvm-elf";
-const DEFAULT_TAG: &str = "v1.1.0";
+const DEFAULT_TAG: &str = "latest";
 const DEFAULT_OUTPUT_DIR: &str = "elf";
 const HELPER_TARGET_SUBDIR: &str = "elf-compilation";